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CVE-2011-0421

33
FAUCET Score

CVE-2011-0421 describes a denial-of-service vulnerability in the Zip extension of PHP versions prior to 5.3.6. Specifically, the _zip_name_locate function can suffer a NULL pointer dereference when processing an empty ZIP archive with locateName or statName operations. This vulnerability has a CVSS score of 4.3 (Medium), indicating it can be exploited remotely with medium attack complexity, resulting in partial availability impact. While not listed in CISA KEV, exploit code for this vulnerability is publicly available via ExploitDB (EDB-17004). Despite this, there is no evidence of active exploitation, and it has received minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 5.3.5CPE matchmatch criteria
cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
1.0CPE matchmatch criteria
cpe:2.3:a:php:php:1.0:*:*:*:*:*:*:*
2.0CPE matchmatch criteria
cpe:2.3:a:php:php:2.0:*:*:*:*:*:*:*
2.0b10CPE matchmatch criteria
cpe:2.3:a:php:php:2.0b10:*:*:*:*:*:*:*
3.0CPE matchmatch criteria
cpe:2.3:a:php:php:3.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

4.3MEDIUM

AV:N/AC:M/Au:N/C:N/I:N/A:P

Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Exploitability Score
8.6
Impact Score
2.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
13.51%
Probability of exploitation in next 30 days
EPSS Percentile
96.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
ExploitDB: EDB-17004 · Mar 18, 2011
This CVE's current EPSS score of 0.1351 is in the 96th percentile among its peer group of 19,958 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

redhatpatch availablevia nvd_reference
View patch
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: php53
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: libzip
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: php

Vendor Advisories (1)

redhatCVE-2011-0421Low

php/libzip: segfault with FL_UNCHANGED on empty archive in zip_name_locate()

Jan 30, 2011

References

bugs.php.net / bug.php
Exploit
lists.apple.com / archives/Security-announce/2011//Oct/msg00003.html
lists.fedoraproject.org / pipermail/package-announce/2011-April/057709.html
lists.fedoraproject.org / pipermail/package-announce/2011-April/057710.html
lists.fedoraproject.org / pipermail/package-announce/2011-March/056642.html
lists.opensuse.org / opensuse-security-announce/2011-05/msg00005.html
marc.info
bugzilla.redhat.com / show_bug.cgi
ExploitPatch
secunia.com / advisories/43621
Vendor Advisory
securityreason.com / achievement_securityalert/96
securityreason.com / securityalert/8146
exchange.xforce.ibmcloud.com / vulnerabilities/66173
support.apple.com / kb/HT5002
svn.php.net / viewvc
Patch
debian.org / security/2011/dsa-2266
exploit-db.com / exploits/17004
Exploit
mandriva.com / security/advisories
mandriva.com / security/advisories
mandriva.com / security/advisories
php.net / archive/2011.php
php.net / ChangeLog-5.php
php.net / releases/5_3_6.php
securityfocus.com / archive/1/517065/100/0/threaded
securityfocus.com / bid/46354
vupen.com / english/advisories/2011/0744
Vendor Advisory
vupen.com / english/advisories/2011/0764
Vendor Advisory
vupen.com / english/advisories/2011/0890
Vendor Advisory