CVE-2011-1156

Exp

feedparser.py in Universal Feed Parser (aka feedparser or python-feedparser) before 5.0.1 allows remote attackers to cause a denial of service (application crash) via a malformed DOCTYPE declaration.

Published: 2011-04-11 Last update: 2026-04-29 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2011-1156 is rated High Exploit Risk (62.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.42%). Core evidence: 3 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2011-1156

EDB-ID Source Kind Published Link
nvd_ref exploit_tag Exploit-DB ↗
nvd_ref exploit_tag Exploit-DB ↗
nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2011-1156

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-30 3.90% 2.42% -1.49%
2 2025-03-29 2.42% 3.90% +1.49%
3 2025-03-17 2.42%

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-1156

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
10.0 2.9 [email protected]

Weakness enumeration for CVE-2011-1156

GitHub Security Advisory for CVE-2011-1156

GHSA-6h52-4vmh-8x4f · Severity: high · Ecosystem: pip — feedparser denial of service vulnerability

OS Trackers for CVE-2011-1156

vendor priority summary link
debian low CVE-2011-1156 low priority: Debian including 1 source packages (feedparser), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2011-1156
ubuntu low CVE-2011-1156 low priority: Ubuntu including 1 source packages (feedparser), 12 status rows across 12 suites (dapper, hardy, karmic, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, upstream): ignored 6, not-affected 5, released 1. https://ubuntu.com/security/CVE-2011-1156

Affected software / configurations for CVE-2011-1156

Vendor Product Version Raw CPE
mark_pilgrim feedparser <= 5.0 cpe:2.3:a:mark_pilgrim:feedparser:*:*:*:*:*:*:*:*
mark_pilgrim feedparser 3.0 cpe:2.3:a:mark_pilgrim:feedparser:3.0:*:*:*:*:*:*:*
mark_pilgrim feedparser 3.0.1 cpe:2.3:a:mark_pilgrim:feedparser:3.0.1:*:*:*:*:*:*:*
mark_pilgrim feedparser 3.1 cpe:2.3:a:mark_pilgrim:feedparser:3.1:*:*:*:*:*:*:*
mark_pilgrim feedparser 3.2 cpe:2.3:a:mark_pilgrim:feedparser:3.2:*:*:*:*:*:*:*
mark_pilgrim feedparser 3.3 cpe:2.3:a:mark_pilgrim:feedparser:3.3:*:*:*:*:*:*:*
mark_pilgrim feedparser 4.0 cpe:2.3:a:mark_pilgrim:feedparser:4.0:*:*:*:*:*:*:*
mark_pilgrim feedparser 4.0.1 cpe:2.3:a:mark_pilgrim:feedparser:4.0.1:*:*:*:*:*:*:*
mark_pilgrim feedparser 4.0.2 cpe:2.3:a:mark_pilgrim:feedparser:4.0.2:*:*:*:*:*:*:*
mark_pilgrim feedparser 4.1 cpe:2.3:a:mark_pilgrim:feedparser:4.1:*:*:*:*:*:*:*

References for CVE-2011-1156

cvelogic Threat Intelligence