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Fencer Vulns
medium 5.3

CVE-2026-44518 json

liboqs: XMSS Buffer Overread Bug

published 2026-05-29 5 mo ago modified 2026-07-21 3 mo ago also EUVD-2026-33412

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. Prior to 0.16.0, an out-of-bounds read has been identified in the XMSS and XMSS^MT stateful signature verification code. When the verification function is called with a signature buffer shorter than the expected signature size for the given parameter set, the implementation does not validate the caller-supplied length and proceeds to read past the end of the buffer. The out-of-bounds bytes are consumed only as input to an internal hash computation and are not returned to the caller, so no oracle exists to leak their contents to an attacker. The primary observable effect is a possible crash (denial of service) of the verifying process if the read crosses into an unmapped memory page. This vulnerability is fixed in 0.16.0.

Patch / fix

  • liboqs SLES for SAP applications 16.0, SLES 16.0 0.16.0-160000.1.1
  • oqs-provider SLES for SAP applications 16.0, SLES 16.0 0.11.0.32-160000.1.1
  • oqs-provider SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 0.11.0.32-150600.3.9.1
  • liboqs SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 0.16.0-150600.3.6.1

suse advisories SUSE-SU-2026:23313-1SUSE-SU-2026:3420-1

  • liboqs openSUSE Leap 16.0 0.16.0-160000.1.1
  • oqs-provider openSUSE Leap 16.0 0.11.0.32-160000.1.1

opensuse advisories openSUSE-SU-2026:21634-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-44518 updated cvss 5.3

liboqs: liboqs: Denial of Service due to out-of-bounds read in XMSS/XMSS^MT signature verification

  • Red Hat Enterprise Linux 10 liboqs
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

  • open-quantum-safe liboqs

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.