USN-8707-1: openCryptoki vulnerabilities

unknownCVE-2026-40253 CVE-2026-23893 CVE-2026-22791

It was discovered that primitive decoders in openCryptoki produced integer underflows when the encoded length was zero. An attacker could possibly use this issue to trigger out-of-bounds reads. (CVE-2026-40253) It was discovered that openCryptoki incorrectly handled symlinks. An attacker in the token-group could possibly use this issue to achieve privilege escalation or access sensitive information. (CVE-2026-23893) It was discovered that the CKM_ECDH_AES_KEY_WRAP implementation had a heap buffer overflow vulnerability. An attacker could possibly use this issue to trigger heap corruption, or denial-of-service. (CVE-2026-22791)

CSIRTS triage

vendor: openCryptoki product: openCryptoki Memory corruption Privilege escalation Information disclosure

What: Integer underflows in decoders cause out-of-bounds reads, symlink handling enables privilege escalation, and heap buffer overflow in CKM_ECDH_AES_KEY_WRAP implementation.
Who is affected: Systems using openCryptoki for cryptographic operations, particularly those with token-group members.
Urgency: Severity unknown; memory corruption, privilege escalation, and information disclosure across multiple components require prioritized patching.
Action: Update openCryptoki to patched version; review token-group membership and audit symlink access in token directories.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Ubuntu Security Notices (INTL · vendor-psirt · site)
Severity: unknown
Published: 2026-08-31
Exploitation: Not in CISA KEV at last sync

Original advisory: https://ubuntu.com/security/notices/USN-8707-1

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-402530.16% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-238930.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-227910.25% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 16% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-40253	coverage & exploitation status	NVD · CVE.org
CVE-2026-23893	coverage & exploitation status	NVD · CVE.org
CVE-2026-22791	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.