CVE-2026-18568 (GCVE-0-2026-18568)

Vulnerability from cvelistv5 – Published: 2026-08-03 14:38 – Updated: 2026-08-03 20:05
VLAI
Title
XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped before any cryptographic check
Summary
XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped before any cryptographic check. verify in lib/XML/Sig.pm counts the `//dsig:Signature` elements into `$numsigs` and iterates over them, but two paths reach `next` before any digest or key check runs: a `SignedInfo/Reference/@URI` that resolves to no element while `$numsigs` is greater than 1, and, when `id_attr` is set, a reference that does not match the requested ID. The loop records nothing about what it checked, so when every signature takes one of those paths control reaches the unconditional `return 1` that ends verify. Two `Signature` elements whose Reference URI names an ID that no element carries is enough, as is one such element combined with `id_attr`. Any caller that passes untrusted XML to verify can receive a true return for a document in which no digest and no signature value was checked; a `cert` or `cert_text` trust anchor does not change this, because no key check runs. Versions up to 0.28 use an XML::XPath based verify that has no such skip and are not affected.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-03 20:05 UTC
CWE
  • CWE-347 - Improper Verification of Cryptographic Signature
Assigner
CPANSec CNA under the redhat root
CNA scorecard C 62/100 over 369 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
TIMLEGGE XML::Sig Affected: 0.29 , < 0.72 (custom)
guessed Create a notification for this product.
Show details on NVD website
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