CVE-2021-42716

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-10-21 · updated 2026-06-17
Weakness: CWE-120

Description

An issue was discovered in stb stb_image.h 2.27. The PNM loader incorrectly interpreted 16-bit PGM files as 8-bit when converting to RGBA, leading to a buffer overflow when later reinterpreting the result as a 16-bit buffer. An attacker could potentially have crashed a service using stb_image, or read up to 1024 bytes of non-consecutive heap data without control over the read location.

Affected products

Fedoraproject Fedora: 33, 34, 35
nothings stb: 2.27

References

https://github.com/nothings/stb/issues/1166
https://github.com/nothings/stb/issues/1225
https://github.com/nothings/stb/pull/1223
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3TDGZFLBOP27LZKLH45WQLSNPSPP7S7Z/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AF2CNP4FVC6LDKNOO4WDCGNDYIP3MPK6/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BEGXBDEMTFGINETMJENBZ6SCHVEJQJSY/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CI23LXPEV2GCDQTJSKO6CIILBDTI3R42/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FTZXHFZD36BGE5P6JF252NZZLKMGCY4T/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G2M5CRSGPRF7G3YB5CLU4FXW7ANNHAYT/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ID6II3RIKAMVGVMC6ZAQIXXYYDMTVC4N/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TXX76TJMZBPN3NU542MGN6B7C7QHRFGB/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VP2YEXEAJWI76FPM7D7VXHWD3WESQEYC/

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