Description
Multiple integer overflows in the evbuffer API in Libevent 1.4.x before 1.4.15, 2.0.x before 2.0.22, and 2.1.x before 2.1.5-beta allow context-dependent attackers to cause a denial of service or possibly have other unspecified impact via "insanely large inputs" to the (1) evbuffer_add, (2) evbuffer_expand, or (3) bufferevent_write function, which triggers a heap-based buffer overflow or an infinite loop. NOTE: this identifier has been SPLIT per ADT3 due to different affected versions. See CVE-2015-6525 for the functions that are only affected in 2.0 and later.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libevent | 2.0.21-stable-2 | — |
| Debian 13 | libevent | 2.0.21-stable-2 | — |
| Debian 12 | libevent | 2.0.21-stable-2 | — |
| Debian 7 | libevent | 2.0.19-stable-3+deb7u1 | DSA-3119-1 |
| Debian 6.0 | libevent | 1.4.13-stable-1+deb6u1 | DLA-137-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | libevent | 2.0.21-stable-1ubuntu1.14.04.1 | USN-2477-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dnscrypt-proxy | 2.1.0-1.2 | openSUSE-SU-2024:10720-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | libevent +2 | 2.0.21-4.amzn2.0.3 | ALAS2-2019-1359 |
Advisories 5
- USN-2477-1 libevent vulnerability Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3119-1 libevent - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-137-1 libevent - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10720-1 dnscrypt-proxy-2.1.0-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2-2019-1359 Moderate: libevent security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Nov 14, 2019
References
- [Libevent-users] 20150105 Advisory: integer overflow in evbuffers for Libevent <= 1.4.14b,2.0.21,2.1.4-alpha [CVE-2014-6272] mailing-list
- DSA-3119 vendor-advisory
- https://puppet.com/security/cve/CVE-2014-6272
- SSA:2016-085-01 vendor-advisory