CVE-2016-2851

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-14. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 25%CVSS: 9.8Exploit: Elevated riskExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
65(Track*)
EG Risk 65/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
25%
EPSS %ILE
98%
KEV
Not listed

Published

April 7, 2016

Last Modified

June 17, 2026

Advisory Details (7)

Auto-updated Aug 18, 2026
⚠️ Active exploitation confirmed. Patch available.
generic Patch Available🟡 PoC Available

libotr 4.1.0 - Memory Corruption - Multiple dos Exploit

https://www.exploit-db.com/exploits/39550/
generic

libotr, Pidgin OTR: Remote execution of arbitrary code (GLSA 201701-10) — Gentoo security

https://security.gentoo.org/glsa/201701-10
generic

[OTR-users] Security Advisory: upgrade to libotr 4.1.1

https://lists.cypherpunks.ca/pipermail/otr-users/2016-March/002581.html
generic

CVE-2016-2851 — PSIRT.COM

http://www.securityfocus.com/bid/84285
generic🔴 Active Exploitation

PSIRT.COM — Product Security Incident Response Team

http://www.securityfocus.com/archive/1/537745/100/0/threaded
generic

[SECURITY] [DSA 3512-1] libotr security update

http://www.debian.org/security/2016/dsa-3512
generic Patch Available🟡 PoC Available

Full Disclosure: Advisory X41-2016-001: Memory Corruption Vulnerability in "libotr"

http://seclists.org/fulldisclosure/2016/Mar/21

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibotr2 (3.2.0-4ubuntu0.3) @ precise2026-05-20ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(6 across 6 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
libotr—4.1.1-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libotr—4.1.1-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libotr—4.1.1-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libotr—4.1.1-1—
Debian:7(1)
PackageVulnerable rangeFixed inDependents
libotr3.2.1-1, 3.2.1-1+deb7u13.2.1-1+deb7u2—
Debian:8(1)
PackageVulnerable rangeFixed inDependents
libotr4.1.0-2, 4.1.0-2+deb8u1~bpo70+14.1.0-2+deb8u1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 5× in last 7d / 22× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 125 total refreshes for this CVE.

  1. 2026-08-19 16:59 UTCEPSS rescore
  2. 2026-08-18 13:43 UTCEPSS rescore
  3. 2026-08-16 14:51 UTCEPSS rescore
  4. 2026-08-16 02:09 UTCEPSS rescore
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  6. 2026-08-12 13:46 UTCEPSS rescore
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  8. 2026-08-10 02:09 UTCOSV refresh
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  20. 2026-07-25 02:41 UTCOSV refresh
  21. 2026-07-23 14:14 UTCEPSS rescore
  22. 2026-07-23 01:22 UTCEG score recompute
  23. 2026-07-22 22:02 UTCEG score recompute
  24. 2026-07-22 14:04 UTCEPSS rescore
  25. 2026-07-21 15:21 UTCEPSS rescore
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  1. 2026-07-21 15:21 UTCEPSS rescore
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  5. 2026-07-18 10:00 UTCEPSS rescore
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  7. 2026-07-16 16:59 UTCEPSS rescore
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  9. 2026-07-15 16:54 UTCEPSS rescore
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  17. 2026-07-07 21:27 UTCOSV refresh
  18. 2026-07-06 16:24 UTCEPSS rescore
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  22. 2026-07-01 15:02 UTCEPSS rescore
  23. 2026-06-30 23:19 UTCEPSS rescore
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  26. 2026-06-28 04:53 UTCEPSS rescore
  27. 2026-06-27 03:05 UTCEPSS rescore
  28. 2026-06-27 03:05 UTCEPSS rescore
  29. 2026-06-25 13:47 UTCEPSS rescore
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  31. 2026-06-24 14:02 UTCEPSS rescore
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  39. 2026-06-19 19:23 UTCEPSS rescore
  40. 2026-06-19 19:23 UTCEPSS rescore
  41. 2026-06-19 09:25 UTCOSV refresh
  42. 2026-06-18 17:50 UTCEPSS rescore
  43. 2026-06-17 17:50 UTCEPSS rescore
  44. 2026-06-17 17:50 UTCEPSS rescore
  45. 2026-06-16 17:50 UTCEPSS rescore
  46. 2026-06-16 17:50 UTCEPSS rescore
  47. 2026-06-15 17:45 UTCEPSS rescore
  48. 2026-06-14 23:14 UTCEPSS rescore
  49. 2026-06-12 23:09 UTCEPSS rescore
  50. 2026-06-12 23:09 UTCEPSS rescore
  51. 2026-06-11 13:57 UTCEPSS rescore
  52. 2026-06-10 22:15 UTCEPSS rescore
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  54. 2026-06-07 15:22 UTCEPSS rescore
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  56. 2026-06-06 13:45 UTCEPSS rescore
  57. 2026-06-05 22:44 UTCEPSS rescore
  58. 2026-06-05 06:08 UTCEPSS rescore
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  60. 2026-06-02 20:10 UTCEPSS rescore
  61. 2026-06-01 13:49 UTCEPSS rescore
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  63. 2026-05-31 22:28 UTCEPSS rescore
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  65. 2026-05-31 00:14 UTCEPSS rescore
  66. 2026-05-30 18:53 UTCOSV refresh
  67. 2026-05-29 13:41 UTCEPSS rescore
  68. 2026-05-28 13:42 UTCEPSS rescore
  69. 2026-05-28 13:42 UTCEPSS rescore
  70. 2026-05-27 13:38 UTCEPSS rescore
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  72. 2026-05-24 16:43 UTCEPSS rescore
  73. 2026-05-22 21:15 UTCEPSS rescore
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  75. 2026-05-21 22:40 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-39550
    First seen Mar 10, 2016

    libotr 4.1.0 - Memory Corruption

    Open source ↗

Frequently asked(5)

What is CVE-2016-2851?
CVE-2016-2851 is a critical vulnerability published on April 7, 2016. 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.
When was CVE-2016-2851 disclosed?
CVE-2016-2851 was first published in the National Vulnerability Database on April 7, 2016, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-2851 actively exploited?
CVE-2016-2851 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25% probability of exploitation in the next 30 days, which ranks it in the top 2.2% of all scored CVEs.
What is the CVSS score of CVE-2016-2851?
CVE-2016-2851 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2016-2851?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-2851, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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