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Fencer Intel
high 7.5

CVE-2015-6525 json

Multiple integer overflows in the evbuffer API in Libevent 2.0.x before 2.0.22 and 2.1.x before 2.1.5-beta allow context-dependent attacker…

published 2015-08-24 11 y ago modified 2026-06-17 4 mo ago also EUVD-2015-6464

cvss
7.5
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.8%
EPSS 4.8% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

Multiple integer overflows in the evbuffer API in Libevent 2.0.x before 2.0.22 and 2.1.x before 2.1.5-beta allow context-dependent attackers to cause a denial of service or possibly have other unspecified impact via "insanely large inputs" to the (1) evbuffer_add, (2) evbuffer_prepend, (3) evbuffer_expand, (4) exbuffer_reserve_space, or (5) evbuffer_read function, which triggers a heap-based buffer overflow or an infinite loop. NOTE: this identifier was SPLIT from CVE-2014-6272 per ADT3 due to different affected versions.

Patch / fix

  • libevent Debian 14, Debian 13, Debian 12 2.0.21-stable-2

debian advisories DEBIAN-CVE-2015-6525

  • libevent Ubuntu 14.04 LTS 2.0.21-stable-1ubuntu1.14.04.1

ubuntu advisories UBUNTU-CVE-2015-6525

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2015-6525 updated cvss 5.1

libevent: multiple integer overflows in the evbuffer APIs

  • Red Hat Enterprise Linux 5 firefox, thunderbird Red Hat Enterprise Linux 6 firefox, thunderbird, chromium-browser Red Hat Enterprise Linux 7 firefox, libevent, thunderbird
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 4 openmpi, nfs-utils Red Hat Enterprise Linux 5 openmpi, libevent Red Hat Enterprise Linux 6 openmpi, libevent Red Hat Enterprise Linux 7 openmpi, openmpi3, compat-openmpi16
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.81% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.