CVE-2026-18089 Vulnerability Analysis & Exploit Details

CVE-2026-18089
Vulnerability Scoring

7.5
/10
Very High Risk

Highly exploitable, CVE-2026-18089 poses a critical security risk that could lead to severe breaches.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-18089 Details

Status: Analyzed

Last updated: 🕘 23 Oct 2026, 21:10 UTC
Originally published on: 🕑 03 Aug 2026, 14:16 UTC

Time between publication and last update: 81 days

CVSS Release: version 3

CVSS3 Source

134c704f-9b21-4f2e-91b3-4a467353bcc0

CVSS3 Type

Secondary

CVSS3 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVE-2026-18089 Vulnerability Summary

CVE-2026-18089: Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass by verifying responses against the response-embedded certificate in verify_xml when no trust anchor is configured. verify_xml in Net::SAML2::Role::VerifyXML runs "return if !$anchors && !$cacert;" as soon as the XML::Sig check succeeds, and that check uses the X.509 certificate taken from the response's own dsig:KeyInfo/dsig:X509Certificate element, so an unanchored response is checked only against the key it carries. Binding::POST declares cacert as an optional Maybe[Str] with no default, so a POST binding built without one takes that path, and _verify_encrypted_assertion returns early the same way with "return $xml unless $cacert;". Any caller that constructs Binding::POST or calls Assertion->new_from_xml without a cacert, cert_text, or anchors argument accepts a response signed by an attacker generated key whose self-signed certificate is embedded in that response, authenticating an arbitrary assertion.

Assessing the Risk of CVE-2026-18089

Access Complexity Graph

The exploitability of CVE-2026-18089 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-18089

With low attack complexity and no required privileges, CVE-2026-18089 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-18089, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-18089, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-18089 has no significant impact on data confidentiality.
  • Integrity: High
    CVE-2026-18089 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: None
    CVE-2026-18089 does not impact system availability.

CVE-2026-18089 References

External References

CWE Common Weakness Enumeration

CWE-347

CAPEC Common Attack Pattern Enumeration and Classification

  • Padding Oracle Crypto Attack CAPEC-463 An adversary is able to efficiently decrypt data without knowing the decryption key if a target system leaks data on whether or not a padding error happened while decrypting the ciphertext. A target system that leaks this type of information becomes the padding oracle and an adversary is able to make use of that oracle to efficiently decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block). In addition to performing decryption, an adversary is also able to produce valid ciphertexts (i.e., perform encryption) by using the padding oracle, all without knowing the encryption key.
  • Signature Spoofing by Improper Validation CAPEC-475 An adversary exploits a cryptographic weakness in the signature verification algorithm implementation to generate a valid signature without knowing the key.

Vulnerable Configurations

  • cpe:2.3:a:timlegge:net\:\:saml2:0.10:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.10:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.11:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.11:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.12:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.12:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.14:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.14:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.15:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.15:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.16:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.16:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.17:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.17:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.19.05:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.19.05:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.20:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.20:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.20.03:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.20.03:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.25:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.25:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.26:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.26:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.27:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.27:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.28:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.28:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.29:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.29:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.30:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.30:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.31:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.31:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.32:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.32:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.33:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.33:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.34:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.34:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.35:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.35:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.36:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.36:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.37:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.37:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.38:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.38:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.39:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.39:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.40:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.40:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.41:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.41:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.42:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.42:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.43:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.43:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.44:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.44:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.45:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.45:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.46:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.46:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.47:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.47:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.48:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.48:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.49:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.49:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.50:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.50:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.51:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.51:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.52:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.52:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.53:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.53:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.54:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.54:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.55:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.55:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.56:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.56:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.57:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.57:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.58:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.58:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.59:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.59:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.60:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.60:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.61:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.61:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.62:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.62:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.63:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.63:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.64:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.64:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.65:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.65:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.66:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.66:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.67:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.67:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.68:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.68:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.69:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.69:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.70:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.70:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.71:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.71:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.72:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.72:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.73:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.73:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.74:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.74:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.75:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.75:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.76:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.76:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.77:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.77:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.78:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.78:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.79:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.79:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.80:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.80:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.81:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.81:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.82:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.82:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.83:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.83:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.84:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.84:*:*:*:*:perl:*:*
  • cpe:2.3:a:timlegge:net\:\:saml2:0.85:*:*:*:*:perl:*:*
    cpe:2.3:a:timlegge:net\:\:saml2:0.85:*:*:*:*:perl:*:*

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