PatchTheCVECVE-2026-5187: Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c
CVE-2026-5187 is a critical-severity flaw (CVSS 9.8) affecting wolfssl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bounds write when outSz equals 1. Second, multiple callers pass sizeof(decOid) (64 bytes on 64-bit platforms) instead of the element count MAX_OID_SZ (32), causing the function to accept crafted OIDs with 33 or mo
Why this priority
- Critical severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-5187?
wolfssl: upgrade to newer than 5.9.0. Exact commands for each OS are on this page.
Is CVE-2026-5187 being exploited?
CVE-2026-5187 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-5187 affect?
CVE-2026-5187 affects wolfssl. Severity is critical (CVSS 9.8). Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bou
How urgent is CVE-2026-5187?
Priority 44/100. Critical severity; Remotely exploitable, no login, no user action
Software pages
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