CVE-2015-6525

CVE-2015-6525 is a high-severity vulnerability in Libevent Project Libevent with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-189.

Key facts

Description

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.

Frequently asked questions

What is CVE-2015-6525?
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.
How severe is CVE-2015-6525?
CVE-2015-6525 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2015-6525 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-6525?
CVE-2015-6525 primarily affects Libevent Project Libevent. In total, 26 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-6525?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2015-6525 published?
CVE-2015-6525 was published on 2015-08-24 and last updated on 2026-06-17.

References

Affected products (26)

More vulnerabilities in Libevent Project Libevent

All CVEs affecting Libevent Project Libevent →

Other CWE-189 (Numeric Errors) vulnerabilities

Browse all CWE-189 (Numeric Errors) vulnerabilities →