CVE-2016-2851

Exp

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: 2016-04-07 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-2851 is rated High Exploit Risk (92.5/100): CVSS Critical severity, with high exploitation likelihood (EPSS 25.40%, 98th percentile). 4 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +4.14% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2016-2851

EDB-ID Source Kind Published Link
39550 exploit_db edb 2016-03-10 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2016-2851

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 21.26% 25.40% +4.14%
2 2026-05-30 23.06% 21.26% -1.80%
3 2025-07-13 — 23.06% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-2851

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.0 CRITICAL
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2016-2851

OS Trackers for CVE-2016-2851

vendor priority summary link
debian not yet assigned CVE-2016-2851 not yet assigned priority: Debian including 1 source packages (libotr), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2016-2851
gentoo normal CVE-2016-2851: 1 GLSA(s) (201701-10), 2 atom(s) (net-libs/libotr, x11-plugins/pidgin-otr); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-2851
suse medium CVE-2016-2851 severity moderate: SUSE including 12 source package names (libotr, libotr-devel, …), 56 product×package rows across 37 product lines (SUSE Linux Enterprise Desktop 11 SP4, SUSE Linux Enterprise Desktop 12, … (37 product lines)): Fixed 42, Known Not Affected 14. https://www.suse.com/security/cve/CVE-2016-2851/
ubuntu medium CVE-2016-2851 medium priority: Ubuntu including 1 source packages (libotr), 4 status rows across 4 suites (precise, trusty, upstream, wily): released 4. https://ubuntu.com/security/CVE-2016-2851

Affected software / configurations for CVE-2016-2851

Vendor Product Version Raw CPE
debian debian_linux 7.0 cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
opensuse leap 42.1 cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:*
opensuse opensuse 13.2 cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:*
cypherpunks libotr <= 4.1.0 cpe:2.3:a:cypherpunks:libotr:*:*:*:*:*:*:*:*

References for CVE-2016-2851

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2016-03/msg00021.html Mailing List
http://lists.opensuse.org/opensuse-security-announce/2016-03/msg00030.html Vendor Advisory
http://seclists.org/fulldisclosure/2016/Mar/21 Exploit Mailing List Third Party Advisory
http://www.debian.org/security/2016/dsa-3512 Third Party Advisory
http://www.securityfocus.com/archive/1/537745/100/0/threaded Third Party Advisory
http://www.securityfocus.com/bid/84285 Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/USN-2926-1 Third Party Advisory
https://lists.cypherpunks.ca/pipermail/otr-users/2016-March/002581.html Exploit
https://security.gentoo.org/glsa/201701-10 Third Party Advisory
https://www.exploit-db.com/exploits/39550/ Third Party Advisory VDB Entry
https://www.x41-dsec.de/lab/advisories/x41-2016-001-libotr/ Exploit
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