CVE-2026-97399 One-byte overread in strncasecmp on Power8
A one-byte overread in glibc's strncasecmp on Power8 can crash applications when processing attacker-controlled strings near memory boundaries.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97399?
CVE-2026-97399 is a low-severity denial of service vulnerability in The GNU C Library glibc, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The strncasecmp function in the GNU C Library 2.24 and later optimized for the Power8 architecture may read one byte beyond the input size limit, which may crash a program when that byte is not readable.
This condition may happen when the input strings to the strncasecmp function are attacker controlled in an application and they match all the way up to the edge of their page and the neighbouring page is either not mapped or is not readable.
Weakness: CWE-126
Which versions are affected by CVE-2026-97399?
How do I fix CVE-2026-97399?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-97399 being exploited?
There is no known exploitation of CVE-2026-97399 in the wild and no public exploit code.
Sources
Also known as AZL-104976, DEBIAN-CVE-2026-97399, GHSA-qhjw-2xw3-v2hv, UBUNTU-CVE-2026-97399.