CVE-2021-3695
A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause…
- Published
- Updated
- Reserved
- Assigned by
- redhat
Description
A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.
Timeline
ID reserved
By redhat
- 11 months later
· 11 months later
Published
- 2 years later
· 2 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium4.5 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L |
- EPSS (exploitation in 30 days)
- 0.47% · top 59% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.5.
Weakness
Affected products
grub2
- affected grub-2.06
References (3)
- https://bugzilla.redhat.com/show_bug.cgi?id=1991685 (opens in a new tab)x_refsource_MISCx_transferred
- GLSA-202209-12 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- https://security.netapp.com/advisory/ntap-20220930-0001/ (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-3695)Record last updated .