mwlib 0.13 through 0.13.4 has a denial of service vulnerability when parsing #iferror magic functions

published 2019-11-12 6 y ago modified 2026-06-16 4 mo ago also EUVD-2012-1143

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 2.1%; EPSS 2.1% chance of exploitation in 30 days, percentile 81%
public exploits: 0; none known

Patch / fix

links 1

openwall.com/lists/oss-security/2012/03/05/20 advisory

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-2012-1109 updated 2025-11-21 cvss 4.3

mwlib: denial of service when parsing #iferror magic functions

Red Hat All currently supported Red Hat products
not affected: vulnerable code not present

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

2.08% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/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

Affected products

Python mwlib

Classification

Weakness

CWE-755 Improper Handling of Exceptional Conditions

References

openwall.com /lists/oss-security/2012/03/05/20
mailing-list, patch, third-party-advisory
bugzilla.redhat.com /show_bug.cgi?id=CVE-2012-1109
issue-tracking, third-party-advisory
securityfocus.com /bid/52577
third-party-advisory, vdb-entry

Sources

CVE List CVE-2012-1109
NVD CVE-2012-1109

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.

Summary