CVE-2021-42040
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control...
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
- Record
CVE-2021-42040- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-835
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
- Record
CVE-2021-42040- Updated
- 2026-11-02
EUVDEUVD-2021-29028 No score
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
- Record
EUVD-2021-29028- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-qrm9-mhjr-qfm7 No score
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control...
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
- Record
GHSA-qrm9-mhjr-qfm7- Weakness
- CWE-835
- Updated
- 2026-11-02
OSV
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
- Record
CVE-2021-42040- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-42040
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
- Record
UBUNTU-CVE-2021-42040- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVBIT-mediawiki-2021-42040 No score
An issue was discovered in MediaWiki through 1.36.2. A parser function related to loop control allowed for an infinite loop (and php-fpm hang) within the Loops extension because egLoopsCountLimit is mishandled. This could lead to memory exhaustion.
- Record
BIT-mediawiki-2021-42040- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mediawikiBitnami |
before 1.36.3 | 1.36.3 |
mediawikiUbuntu:18.04:LTS |
All versions, plus listed versions 1:1.27.3-11:1.27.4-11:1.27.4-21:1.27.4-3 |
None known |
mediawikiUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 1:1.31.2-1ubuntu11:1.31.5-11:1.31.5-1ubuntu11:1.31.5-21:1.31.5-3 Show 4 moreShow less1:1.31.5-3ubuntu11:1.31.6-11:1.31.7-11:1.31.7-1ubuntu0.1~esm1 |
None known |
mediawikiUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 1:1.35.3-11:1.35.4-11:1.35.5-11:1.35.5-1ubuntu11:1.35.5-1ubuntu21:1.35.5-1ubuntu31:1.35.6-11:1.35.6-1ubuntu0.1~esm1 |
None known |
mediawikiUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 1:1.39.4-21:1.39.5-11:1.39.6-11:1.39.7-11:1.39.7-1ubuntu0.1~esm1 |
None known |
mediawikiUbuntu:25.10 |
All versions, plus listed versions 1:1.43.1+dfsg-11:1.43.1+dfsg-21:1.43.3+dfsg-1 |
None known |
mediawikiUbuntu:26.10 |
All versions, plus listed versions 1:1.43.8+dfsg-21:1.43.9+dfsg-11:1.43.9+dfsg-1ubuntu1 |
None known |
mediawikiUbuntu:26.04:LTS |
All versions, plus listed versions 1:1.43.3+dfsg-11:1.43.5+dfsg-11:1.43.6+dfsg-21:1.43.8+dfsg-11:1.43.8+dfsg-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-42040 is a high vulnerability (CVSS 7.5) in Mediawiki, published October 6, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.16%, the 67th percentile. Fixed in mediawiki 1.36.3.