CVE-2016-2851Libotr Memory Corruption
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.
Published Apr 7, 2016 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2016-2851, DSA-3512-1, SUSE-SU-2016:0706-1, SUSE-SU-2016:0707-1, UBUNTU-CVE-2016-2851
Key Facts
Patch immediately- CVE-2016-2851 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Libotr (Cypherpunks), Debian Linux, Leap (Opensuse) and 7 more products.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 25% probability of exploitation in the next 30 days.
- Fixed versions are available, including Libotr 4.1.0, Libotr 3.2.0-10.5.1, Libotr 3.2.1-1+deb7u2.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v3.1
9.8
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
25%
Higher than 97.9% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
44/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
1
Proof-of-concept links
In-the-wild evidence
3
Reports of active use
Advisories And Exploit References
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.
Affected Products
51 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| LibotrCypherpunks | See advisory | 4.1.0 |
| Debian LinuxDebian | 7.0, 8.0 | n/a |
| LeapOpensuse | 42.1 | n/a |
| OpensuseOpensuse | 13.2 | n/a |
| libotr2-develsuse | See advisory | 3.2.1-13.1 |
Patched Releases
Libotr
4.1.0, 3.2.0-10.5.1, 3.2.1-1+deb7u2, 4.0.0-2.2ubuntu1.1, 4.0.0-9.1, 4.1.0-2+deb8u1, 4.1.1-1, 4.1.1-4.1
libotr-devel
3.2.0-10.5.1, 4.0.0-9.1, 4.1.1-1.6, 4.1.1-4.1
libotr-tools
4.1.1-1.6, 4.1.1-4.1
libotr2
3.2.0-10.5.1, 3.2.1-13.1
libotr2-devel
3.2.1-13.1
libotr2-tools
3.2.1-13.1
libotr5
4.0.0-9.1, 4.1.1-1.6, 4.1.1-4.1
Timeline
Publicly disclosed
Apr 7, 2016
Last updated
Aug 4, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
- advisorysecurity-tracker.debian.org · CVE-2016-2851
- advisoryubuntu.com · CVE-2016-2851
- advisorycve.org · CVERecord
- advisoryopenSUSE-SU-2016:0732
- advisorybugzilla.suse.com · 969785
FAQ
Common Questions.
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.
Affected: Libotr (Cypherpunks); Debian Linux versions 7.0, 8.0; Leap (Opensuse) versions 42.1, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Libotr 4.1.0, Libotr 3.2.0-10.5.1, Libotr 3.2.1-1+deb7u2.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Is CVE-2016-2851 On Your Attack Surface?
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