SB2026082528 - Multiple vulnerabilities in XMLSecLibs

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Main Vulnerability Database SB2026082528

SB2026082528 - Multiple vulnerabilities in XMLSecLibs

Published: August 25, 2026

Security Bulletin ID SB2026082528
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 7
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 86% Low 14%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 7 vulnerabilities.


1) XPath Injection (CVE-ID: N/A)

CWE-ID: CWE-643 - Improper Neutralization of Data within XPath Expressions

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper neutralization of data within XPath expressions in processTransforms() when validating references that include REC-xpath-19991116 Transform elements. A remote attacker can supply a crafted XPath expression to cause a denial of service.

Only instances that enable XMLSecurityDSig::$allowXPathTransforms on the verification path are vulnerable.


2) Observable discrepancy (CVE-ID: N/A)

CWE-ID: CWE-203 - Observable discrepancy

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to decrypt protected message content.

The vulnerability exists due to observable discrepancy in rsa-1_5 key transport decryption handling when processing encrypted XML data. A remote attacker can send specially crafted encrypted data to decrypt protected message content.

Exploitation requires RSA PKCS#1 v1.5 key transport to be enabled.


3) Information Exposure Through Timing Discrepancy (CVE-ID: N/A)

CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy

CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to recover valid message authentication codes.

The vulnerability exists due to an observable timing discrepancy in XMLSecurityKey::verifySignature() when verifying HMAC-SHA1 signatures. A remote attacker can measure response timing differences to recover valid message authentication codes.

Exploitation may be possible byte-by-byte under favorable network conditions.


4) Insufficient verification of data authenticity (CVE-ID: N/A)

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to forge signatures.

The vulnerability exists due to insufficient verification of data authenticity in verify() and locateKey() when verifying signed XML documents with a caller-supplied key. A remote attacker can supply a crafted signature that downgrades the signature method to hmac-sha1 to forge signatures.

The issue arises because the document\'s SignatureMethod was not always bound to the algorithm of the caller-supplied key, allowing RSA public key material to be treated as an HMAC secret.


5) XML External Entity injection (CVE-ID: N/A)

CWE-ID: CWE-611 - Improper Restriction of XML External Entity Reference ('XXE')

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to disclose sensitive information and perform server-side request forgery.

The vulnerability exists due to improper restriction of xml external entity reference in the decryptNode() method in XMLSecEnc.php when parsing attacker-controlled decrypted xml content. A remote attacker can inject a crafted doctype in encrypted plaintext to disclose sensitive information and perform server-side request forgery.

In SAML deployments, the service provider public encryption key may be available in metadata, making attacker-controlled ciphertext achievable. The issue affects PHP versions earlier than 8.0 where external entity loading is enabled by default.


6) Observable discrepancy (CVE-ID: N/A)

CWE-ID: CWE-203 - Observable discrepancy

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to disclose encrypted XML content.

The vulnerability exists due to observable discrepancy in symmetric CBC decryption and ISO 10126 unpadding when processing encrypted XML content. A remote attacker can submit crafted ciphertext and distinguish decryption failures to disclose encrypted XML content.

All symmetric and asymmetric decryption failures were distinguishable before normalization to a generic decryption error.


7) Improper Verification of Cryptographic Signature (CVE-ID: N/A)

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

CVSSv4: 0 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to bypass signature verification.

The vulnerability exists due to improper verification of cryptographic signature in XMLSecurityDSig::locateSignature() and verifyDocument() when processing XML documents containing a DOCTYPE with entity references in Id attributes. A remote attacker can supply a specially crafted XML document to bypass signature verification.

Applications that disable the default DOCTYPE rejection behavior remain exposed, and the issue can cause signature verification to succeed on a different node than the application reads.


Remediation

Install update from vendor's website.

References