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NVD / CVE Program· CNA mitre

CVE-2016-2851: 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…

CriticalCVSS 9.8 · v3.0—Proof of concept Fix available

Noroxi assessment

Priority: Plan (action score 46/100)

  • Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 24.2% (FIRST EPSS); higher than 97.8% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: libotr (Debian:12) 4.1.1-1; libotr (Debian:7) 3.2.1-1+deb7u2; libotr (Debian:8) 4.1.0-2+deb8u1.

Add it to your regular patch cycle. Upgrade to libotr (Debian:12) 4.1.1-1; libotr (Debian:7) 3.2.1-1+deb7u2; libotr (Debian:8) 4.1.0-2+deb8u1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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
Jun 16, 2026
EPSS
24.2% · 97th percentile

Report tools

JSON

Action score

46

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
7 / 30 · 24.2%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
debiandebian linux
opensuseleap
opensuseopensuse
cypherpunkslibotr

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • cypherpunks libotrup to 4.1.0 inclusive
  • debian debian linux7.0
  • debian debian linux8.0
  • opensuse leap42.1
  • opensuse opensuse13.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12libotrbefore 4.1.1-14.1.1-1
Debian:7libotrbefore 3.2.1-1+deb7u23.2.1-1+deb7u2
Debian:8libotrbefore 4.1.0-2+deb8u14.1.0-2+deb8u1
SUSE:Linux Enterprise Desktop 12libotrbefore 4.0.0-9.14.0.0-9.1
SUSE:Linux Enterprise Software Development Kit 11 SP4libotrbefore 3.2.0-10.5.13.2.0-10.5.1

Same product

debian: all records

Other highest-scoring records for the same primary product.

  • CVE-2016-9079A use-after-free vulnerability in SVG Animation has been discovered.KEV
    86Now
  • CVE-2024-44308The issue was addressed with improved checks.KEV
    68This week
  • CVE-2021-25216A second vulnerability in BIND's GSSAPI security policy negotiation can be targeted by a buffer overflow attack
    64This week

Published before and after this one in the same product

  • ← EarlierCVE-2016-2856Mar 13, 2016 · pt_chown in the glibc package before 2.19-18+deb8u4 on Debian jessie; the elibc package before 2.15-0ubuntu10.14 on Ubuntu 12.04 LTS and…
    33Monitor
  • ← EarlierCVE-2016-2098Apr 7, 2016 · Action Pack in Ruby on Rails before 3.2.22.2, 4.x before 4.1.14.2, and 4.2.x before 4.2.5.2 allows remote attackers to execute arbitrary…
    60This week
  • Later →CVE-2012-6698Apr 11, 2016 · The decode_search function in dhcp.c in dhcpcd 3.x allows remote DHCP servers to cause a denial of service (out-of-bounds write) via a…
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:libotr4.1.1-1 · Debian:12Package registry (OSV)
suse:libotr3.2.0-10.5.1 · SUSE:Linux Enterprise Software Development Kit 11 SP4Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrydos2016-03-10

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-29 d
  2. Published
  3. TodayNov 14, 2026+3872 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Not on record for this CVE: patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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