CVE-2021-42715

An issue was discovered in stb stb_image.h 1.33 through 2.27. The HDR loader parsed truncated end-of-file RLE scanlines as an infinite sequence of zero-length runs. An attacker could potentially have caused denial of service in applications using stb_image by submitting crafted HDR files.

Published: 2021-10-21 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-42715 is rated Moderate Risk (45.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.21%). EPSS rose +1.05% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-42715

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.17% 1.21% +1.05%
2 2026-03-09 0.14% 0.17% +0.03%
3 2026-03-02 — 0.14% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-42715

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-42715

OS Trackers for CVE-2021-42715

vendor priority summary link
debian not yet assigned CVE-2021-42715 not yet assigned priority: Debian including 1 source packages (libstb), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2021-42715
gentoo normal CVE-2021-42715: 1 GLSA(s) (202409-15), 1 atom(s) (dev-libs/stb); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-42715
redhat medium — https://access.redhat.com/security/cve/CVE-2021-42715
ubuntu medium CVE-2021-42715 medium priority: Ubuntu including 1 source packages (libstb), 14 status rows across 14 suites (focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 9, needs-triage 5. https://ubuntu.com/security/CVE-2021-42715

Affected software / configurations for CVE-2021-42715

Vendor Product Version Raw CPE
nothings stb_image.h >= 1.33, <= 2.27 cpe:2.3:a:nothings:stb_image.h:*:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2021-42715

URL Tags
https://github.com/nothings/stb/issues/1224 Issue Tracking Third Party Advisory
https://github.com/nothings/stb/pull/1223 Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/01/msg00045.html Mailing List Third Party Advisory
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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