Is CVE-2026-3949 in the CISA KEV catalog?

No. CVE-2026-3949 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-3949?

CVE-2026-3949 has a CVSS v3 base score of 3.3 (LOW).

What is the EPSS score for CVE-2026-3949?

CVE-2026-3949 has an EPSS score of 0.12% (2th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-3949?

Upgrade libheif on debian unstable to 1.23.1-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-3949

LOW

3.3

CVSS v3

NVD

Description

A vulnerability was determined in strukturag libheif up to 1.21.2. This affects the function vvdec_push_data2 of the file libheif/plugins/decoder_vvdec.cc of the component HEIF File Parser. Executing a manipulation of the argument size can lead to out-of-bounds read. The attack needs to be launched locally. The exploit has been publicly disclosed and may be utilized. This patch is called b97c8b5f198b27f375127cd597a35f2113544d03. It is advisable to implement a patch to correct this issue.

CWE-119Buffer Overflow CWE-125Out-of-bounds Read

How to fix

Remediation Available

libheifDebian

Fixed in:1.23.1-1CVE-2026-3949

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.12%probability of exploitation in 30 days

2ndpercentile

Low risk: more likely to be exploited than 2% of all known CVEs.

References

Other references8

Related Vulnerabilities

Other CWE-119 (Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-4966	Critical	9.4	100%	KEV + Ransom	Fix
CVE-2017-11882	High	7.8	100%	KEV + Ransom	-
CVE-2020-0796	Critical	10.0	100%	KEV + Ransom	-
CVE-2008-4250	Critical	9.8	99%	KEV	-
CVE-2017-15944	Critical	9.8	98%	KEV	Fix
CVE-2015-0014	High	10.0	97%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.