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Fencer Intel
high 7.5

CVE-2009-5155 json

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 c…

published 7y ago modified 4mo ago also EUVD-2009-5109

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.9%
EPSS 3.9% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

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.

Patch / fix

  • gnu glibc 2.28
  • glibc Debian 14, Debian 13, Debian 12 2.28-1
  • gnulib Debian 14, Debian 13, Debian 12 20140202+stable-3.2

debian advisories DEBIAN-CVE-2009-5155

  • glibc Ubuntu 16.04 LTS 2.23-0ubuntu11.3

ubuntu advisories UBUNTU-CVE-2009-5155

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • glibc SLES 12 SP3-BCL, SLES 12 SP2-BCL, OpenStack Cloud Crowbar 8 +9 more 2.22-62.22.5
  • glibc SLE Module for Development Tools 15 SP1, SLE Module for Development Tools 15, SLE Module for Basesystem 15 SP1 +1 more 2.26-13.24.1
  • glibc SLES for SAP 12 SP4, SLES 12 SP4, SLED 12 SP4 +1 more 2.22-100.8.1

suse advisories SUSE-SU-2019:1958-1SUSE-SU-2019:1958-2SUSE-SU-2019:1877-1SUSE-SU-2019:1102-1

  • glibc openSUSE Tumbleweed 2.34-1.2

opensuse advisories openSUSE-SU-2024:10792-1

Is CVE-2009-5155 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-5155 updated cvss 7.5

glibc: parse_reg_exp in posix/regcomp.c misparses alternatives leading to denial of service or trigger incorrect result

  • Red Hat Enterprise Linux 5 glibc Red Hat Enterprise Linux 6 nscd, glibc, glibc-utils, glibc-common
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 nscd, glibc, glibc-utils, glibc-common
    affected: no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.91% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • debbugs.gnu.org https://debbugs.gnu.org/cgi/bugreport.cgi?bug=32806 referenced PoC, tagged "exploit" by a source, unverified
  • sourceware.org https://sourceware.org/bugzilla/show_bug.cgi?id=18986 referenced PoC, tagged "exploit" by a source, unverified
  • debbugs.gnu.org https://debbugs.gnu.org/cgi/bugreport.cgi?bug=34238 referenced PoC, tagged "exploit" by a source, unverified
  • sourceware.org https://sourceware.org/bugzilla/show_bug.cgi?id=11053 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-19 Data Processing Errors

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.