CVE-2009-5155

Status: ModifiedHigh (7.5)—
In the GNU C Library (aka glibc or libc6) before 2.28, parse_reg_exp in posix/regcomp.c misparses alternatives, which allows attackers to cause a denial of service (assertion failure and application exit) or trigger an incorrect result by attempting a regular-expression match.
CVSS

Version: 3.0
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base score: 7.5
Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 3.91%
Percentile among all scored CVEs: 90
Score date: 10/7/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (4)

GNU — Glibc Netapp — Cloud Backup Netapp — Ontap Select Deploy Administration Utility Netapp — Steelstore Cloud Integrated Storage
CWEs

CWE-19
References

Raw JSON (NVD)

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  "lastModified": "2026-06-16T23:15:11.070",
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