Description
Integer overflow in proto.c in libotr before 4.1.1 on 64-bit platforms allows remote attackers to cause a denial of service (memory corruption and application crash) or execute arbitrary code via a series of large OTR messages, which triggers a heap-based buffer overflow.
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 | libotr | 4.1.1-1 | — |
| Debian 13 | libotr | 4.1.1-1 | — |
| Debian 12 | libotr | 4.1.1-1 | — |
| Debian 8 | libotr | 4.1.0-2+deb8u1 | DSA-3512-1 |
| Debian 7 | libotr | 3.2.1-1+deb7u2 | DSA-3512-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | libotr | 4.0.0-2.2ubuntu1.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | libotr | 4.0.0-9.1 | SUSE-SU-2016:0707-1 |
| SLES 12 | libotr | 4.0.0-9.1 | SUSE-SU-2016:0707-1 |
| SLES 11 SP4 | libotr | 3.2.0-10.5.1 | SUSE-SU-2016:0706-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | libotr | 4.0.0-9.1 | SUSE-SU-2016:0707-1 |
| SLES for SAP 12 | libotr | 4.0.0-9.1 | SUSE-SU-2016:0707-1 |
| SLES for SAP 11 SP4 | libotr | 3.2.0-10.5.1 | SUSE-SU-2016:0706-1 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- libotr 4.1.0 - Memory Corruption EDB-39550 · dos · Mar 10, 2016
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 3
- DSA-3512-1 libotr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:0707-1 Security update for libotr SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:0706-1 Security update for libotr SUSE / openSUSE Security Updates · Feb 4, 2026
References
- USN-2926-1 vendor-advisory
- 20160309 Advisory X41-2016-001: Memory Corruption Vulnerability in "libotr" mailing-list
- DSA-3512 vendor-advisory
- GLSA-201701-10 vendor-advisory
- 39550 exploit
- 84285 vdb-entry
- 20160309 Advisory X41-2016-001: Memory Corruption Vulnerability in "libotr" mailing-list
- https://www.x41-dsec.de/lab/advisories/x41-2016-001-libotr/
- openSUSE-SU-2016:0708 vendor-advisory
- [OTR-users] 20160309 Security Advisory: upgrade to libotr 4.1.1 mailing-list
- openSUSE-SU-2016:0732 vendor-advisory