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CVE-2026-6791

MEDIUMCVSS 6.6/10EPSS 0.21%

Last modified

CVE-2026-6791 is a medium-severity vulnerability rated 6.6/10 on the CVSS scale. When expanding paths that begin with a tilde (~) followed by a username, the internal parse_tilde function extracts the username to determine the user's home directory. The implementation allocates memory for this username directly on the stack using the strndupa macro. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

When expanding paths that begin with a tilde (~) followed by a username, the internal parse_tilde function extracts the username to determine the user's home directory. The implementation allocates memory for this username directly on the stack using the strndupa macro. Because the size of this allocation was determined by the length of the user-supplied input without any bounds checks, passing an excessively long username e.g. thousands of characters, forces the thread to exhaust its stack space. Thus if an application passes untrusted, attacker-controlled input to the wordexp function, an attacker can trigger a stack clash.

Metrics

CVSS 4.0
6.6/10

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:L/SA:H/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.21%

10.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
The GNU C Libraryglibc>= 2.0, <= 2.43

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-6791?
When expanding paths that begin with a tilde (~) followed by a username, the internal parse_tilde function extracts the username to determine the user's home directory. The implementation allocates memory for this username directly on the stack using the strndupa macro. Because the size of this allocation was determined by the length of the user-supplied input without any bounds checks, passing an excessively long username e.g. thousands of characters, forces the thread to exhaust its stack space. Thus if an application passes untrusted, attacker-controlled input to the wordexp function, an attacker can trigger a stack clash.
How severe is CVE-2026-6791?
CVE-2026-6791 has a CVSS score of 6.6/10 (MEDIUM severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-6791?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST