Description
Stack-based buffer overflow in the evutil_parse_sockaddr_port function in evutil.c in libevent before 2.1.6-beta allows attackers to cause a denial of service (segmentation fault) via vectors involving a long string in brackets in the ip_as_string argument.
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-3 | — |
| Debian 13 | libevent | 2.0.21-stable-3 | — |
| Debian 12 | libevent | 2.0.21-stable-3 | — |
| Debian 8 | libevent | 2.0.21-stable-2+deb8u1 | DSA-3789-1 |
| Debian 7 | libevent | 2.0.19-stable-3+deb7u2 | DLA-824-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | firefox | 53.0+build6-0ubuntu0.16.04.1 | — |
| Ubuntu 16.04 LTS | libevent | 2.0.21-stable-2ubuntu0.16.04.1 | USN-3228-1 |
| Ubuntu 16.04 LTS | thunderbird | 1:52.1.1+build1-0ubuntu0.16.04.1 | USN-3278-1 |
| Ubuntu 14.04 LTS | firefox | 53.0+build6-0ubuntu0.14.04.1 | — |
| Ubuntu 14.04 LTS | libevent | 2.0.21-stable-1ubuntu1.14.04.2 | USN-3228-1 |
| Ubuntu 14.04 LTS | thunderbird | 1:52.1.1+build1-0ubuntu0.14.04.1 | USN-3278-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | firefox | 52.1.0-2.el7_3 | RHSA-2017:1106 |
| RHEL 7 | thunderbird | 52.1.0-1.el7_3 | RHSA-2017:1201 |
| RHEL 6 | firefox | 52.1.0-2.el6_9 | RHSA-2017:1104 |
| RHEL 6 | thunderbird | 52.1.0-1.el6_9 | RHSA-2017:1201 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | libevent | 2.0.21-6.3.1 | SUSE-SU-2018:0200-1 |
| SLES 12 SP2 | MozillaFirefox | 52.2.0esr-108.3 | SUSE-SU-2017:1669-1 |
| SLES 12 SP2 | MozillaFirefox-branding-SLE | 52-31.1 | SUSE-SU-2017:1669-1 |
| SLES 12 SP2 | libevent | 2.0.21-6.3.1 | SUSE-SU-2018:0200-1 |
| SLES 12 SP1 | MozillaFirefox | 52.2.0esr-108.3 | SUSE-SU-2017:1669-1 |
| SLES 12 SP1 | MozillaFirefox-branding-SLE | 52-31.1 | SUSE-SU-2017:1669-1 |
| SLES 12 | MozillaFirefox | 52.2.0esr-108.3 | SUSE-SU-2017:1669-1 |
| SLES 12 | MozillaFirefox-branding-SLE | 52-31.1 | SUSE-SU-2017:1669-1 |
| SLES 11 SP4 | MozillaFirefox | 52.2.0esr-72.5.2 | SUSE-SU-2017:2235-1 |
| SLES 11 SP4 | MozillaFirefox-branding-SLED | 52-24.3.44 | SUSE-SU-2017:2235-1 |
| SLES 11 SP4 | firefox-gcc5 +1 | 5.3.1+r233831-7.1 | SUSE-SU-2017:2235-1 |
| SLES 11 SP4 | libevent | 1.4.5-24.24.3.1 | SUSE-SU-2018:0263-1 |
| SLES 11 SP4 | mozilla-nss | 3.29.5-47.3.2 | SUSE-SU-2017:2235-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 11 SP3 | MozillaFirefox | 52.2.0esr-72.5.2 | SUSE-SU-2017:2235-1 |
| SLES 11 SP3 | MozillaFirefox-branding-SLED | 52-24.3.44 | SUSE-SU-2017:2235-1 |
| SLES 11 SP3 | firefox-gcc5 +1 | 5.3.1+r233831-7.1 | SUSE-SU-2017:2235-1 |
| SLES 11 SP3 | mozilla-nss | 3.29.5-47.3.2 | SUSE-SU-2017:2235-1 |
| SLES for SAP 12 SP3 | libevent | 2.0.21-6.3.1 | SUSE-SU-2018:0200-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 52.2.0esr-108.3 | SUSE-SU-2017:1669-1 |
| SLES for SAP 12 SP2 | MozillaFirefox-branding-SLE | 52-31.1 | SUSE-SU-2017:1669-1 |
| SLES for SAP 12 SP2 | libevent | 2.0.21-6.3.1 | SUSE-SU-2018:0200-1 |
| SLES for SAP 12 SP1 | MozillaFirefox | 52.2.0esr-108.3 | SUSE-SU-2017:1669-1 |
| SLES for SAP 12 SP1 | MozillaFirefox-branding-SLE | 52-31.1 | SUSE-SU-2017:1669-1 |
| SLES for SAP 12 | MozillaFirefox | 52.2.0esr-108.3 | SUSE-SU-2017:1669-1 |
| SLES for SAP 12 | MozillaFirefox-branding-SLE | 52-31.1 | SUSE-SU-2017:1669-1 |
| SLES for SAP 11 SP4 | MozillaFirefox | 52.2.0esr-72.5.2 | SUSE-SU-2017:2235-1 |
| SLES for SAP 11 SP4 | MozillaFirefox-branding-SLED | 52-24.3.44 | SUSE-SU-2017:2235-1 |
| SLES for SAP 11 SP4 | firefox-gcc5 +1 | 5.3.1+r233831-7.1 | SUSE-SU-2017:2235-1 |
| SLES for SAP 11 SP4 | libevent | 1.4.5-24.24.3.1 | SUSE-SU-2018:0263-1 |
| SLES for SAP 11 SP4 | mozilla-nss | 3.29.5-47.3.2 | SUSE-SU-2017:2235-1 |
| SUSE OpenStack Cloud 6 | MozillaFirefox | 52.2.0esr-108.3 | SUSE-SU-2017:1669-1 |
| SUSE OpenStack Cloud 6 | MozillaFirefox-branding-SLE | 52-31.1 | SUSE-SU-2017:1669-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | MozillaFirefox | 52.2.0esr-72.5.2 | SUSE-SU-2017:2235-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | MozillaFirefox-branding-SLED | 52-24.3.44 | SUSE-SU-2017:2235-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | firefox-gcc5 +1 | 5.3.1+r233831-7.1 | SUSE-SU-2017:2235-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | mozilla-nss | 3.29.5-47.3.2 | SUSE-SU-2017:2235-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libevent | 2.1.8-r0 | — |
| Alpine v3.23 | libevent | 2.1.8-r0 | — |
| Alpine v3.22 | libevent | 2.1.8-r0 | — |
| Alpine v3.21 | libevent | 2.1.8-r0 | — |
| Alpine v3.20 | libevent | 2.1.8-r0 | — |
Show 18 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | libevent | 2.1.8-r0 | — |
| Alpine v3.18 | libevent | 2.1.8-r0 | — |
| Alpine v3.17 | libevent | 2.1.8-r0 | — |
| Alpine v3.16 | libevent | 2.1.8-r0 | — |
| Alpine v3.15 | libevent | 2.1.8-r0 | — |
| Alpine v3.14 | libevent | 2.1.8-r0 | — |
| Alpine v3.13 | libevent | 2.1.8-r0 | — |
| Alpine v3.12 | libevent | 2.1.8-r0 | — |
| Alpine v3.11 | libevent | 2.1.8-r0 | — |
| Alpine v3.10 | libevent | 2.1.8-r0 | — |
| Alpine v3.9 | libevent | 2.1.8-r0 | — |
| Alpine v3.8 | libevent | 2.1.8-r0 | — |
| Alpine v3.7 | libevent | 2.1.8-r0 | — |
| Alpine v3.6 | libevent | 2.1.8-r0 | — |
| Alpine v3.5 | libevent | 2.0.22-r2 | — |
| Alpine v3.4 | libevent | 2.0.22-r1 | — |
| Alpine v3.3 | libevent | 2.0.22-r1 | — |
| Alpine v3.2 | libevent | 2.0.22-r1 | — |
Advisories 11
- USN-3278-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- RHSA-2017:1201 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2017:1104 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2017:1106 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- USN-3228-1 libevent vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-824-1 libevent - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3789-1 libevent - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2017:2235-1 Security update for MozillaFirefox, MozillaFirefox-branding-SLED, firefox-gcc5, mozilla-nss SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:0200-1 Security update for libevent SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:1669-1 Security update for MozillaFirefox, MozillaFirefox-branding-SLE SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:0263-1 Security update for libevent SUSE / openSUSE Security Updates · Feb 4, 2026
References
- 96014 vdb-entry
- RHSA-2017:1106 vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2017-12/
- DSA-3789 vendor-advisory
- [oss-security] 20170202 Re: Bugs fixed in libevent 2.1.6 mailing-list
- https://www.mozilla.org/security/advisories/mfsa2017-11/
- GLSA-201705-01 vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2017-10/
- https://www.mozilla.org/security/advisories/mfsa2017-13/
- [oss-security] 20170131 Bugs fixed in libevent 2.1.6 mailing-list
- 1038320 vdb-entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1343453
- https://github.com/libevent/libevent/issues/318
- https://github.com/libevent/libevent/blob/release-2.1.6-beta/ChangeLog
- RHSA-2017:1104 vendor-advisory
- https://github.com/libevent/libevent/commit/329acc18a0768c21ba22522f01a5c7f46cacc4d5
- RHSA-2017:1201 vendor-advisory