CVE-2023-45666

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 1.0%, top 42% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

stb_image is a single file MIT licensed library for processing images. It may look like stbi__load_gif_main doesn’t give guarantees about the content of output value *delays upon failure. Although it sets *delays to zero at the beginning, it doesn’t do it in case the image is not recognized as GIF and a call to stbi__load_gif_main_outofmem only frees possibly allocated memory in *delays without resetting it to zero. Thus it would be fair to say the caller of stbi__load_gif_main is responsible to free the allocated memory in *delays only if stbi__load_gif_main returns a non null value. However at the same time the function may return null value, but fail to free the memory in *delays if internally stbi__convert_format is called and fails. Thus the issue may lead to a memory leak if the caller chooses to free delays only when stbi__load_gif_main didn’t fail or to a double-free if the delays is always freed

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
59%
KEV
Not listed

Published

October 21, 2023

Last Modified

June 17, 2026

Advisory Details (6)

Auto-updated Sep 7, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet. Sources: github.
generic

[SECURITY] Fedora 37 Update: stb-0^20231011gitbeebb24-12.fc37 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/[email protected]/message/QVABVF4GEM6BYD5L4L64RCRSXUHY6LGN/
generic

[SECURITY] Fedora 38 Update: stb-0^20231011gitbeebb24-12.fc38 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/[email protected]/message/NMXKOKPP4BKTNUTF5KSRDQAWOUILQZNO/
generic🔴 Active Exploitation

stb/stb_image.h at 5736b15f7ea0ffb08dd38af21067c314d6a3aae9 · nothings/stb · GitHub

https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_image.h#L6962-L7045
generic🔴 Active Exploitation

stb/stb_image.h at 5736b15f7ea0ffb08dd38af21067c314d6a3aae9 · nothings/stb · GitHub

https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_image.h#L6957
github

GHSL-2023-145_GHSL-2023-151/GHSL-2023-165_GHSL-2023-172: Several memory access violations in stb_image and stb_vorbis | GitHub Security Lab

https://securitylab.github.com/advisories/GHSL-2023-145_GHSL-2023-151_stb_image_h/
generic

[SECURITY] Fedora 39 Update: usd-23.08-2.fc39 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/[email protected]/message/UVQ7ONFH5GWLMXYEAJG32A3EUKUCEVCR/

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
libstb0.0~git20200713.b42009b+ds-1 ... 0.0~git20250907.fede005+ds-1 (12 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libstb0.0~git20220908.8b5f1f3+ds-1 ... 0.0~git20250907.fede005+ds-1 (8 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libstb0.0~git20241109.5c20573+ds-1, 0.0~git20250907.fede005+ds-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libstb0.0~git20241109.5c20573+ds-1, 0.0~git20250907.fede005+ds-1——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 35× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 166 total refreshes for this CVE.

  1. 2026-09-07 15:59 UTCEPSS rescore
  2. 2026-09-06 13:46 UTCEPSS rescore
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  7. 2026-09-03 14:59 UTCOSV refresh
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  1. 2026-08-17 04:23 UTCOSV refresh
  2. 2026-08-16 14:54 UTCEPSS rescore
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  21. 2026-08-01 23:06 UTCOSV refresh
  22. 2026-08-01 04:14 UTCEPSS rescore
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  34. 2026-07-23 02:27 UTCEG score recompute
  35. 2026-07-22 23:13 UTCEG score recompute▲ 2.50
  36. 2026-07-22 14:06 UTCEPSS rescore
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  48. 2026-07-15 06:19 UTCOSV refresh
  49. 2026-07-15 01:59 UTCEPSS rescore
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  67. 2026-07-02 16:59 UTCEPSS rescore
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  69. 2026-06-30 23:21 UTCEPSS rescore
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  73. 2026-06-28 04:55 UTCEPSS rescore
  74. 2026-06-27 06:34 UTCOSV refresh
  75. 2026-06-27 03:07 UTCEPSS rescore

Frequently asked(5)

What is CVE-2023-45666?
CVE-2023-45666 is a critical vulnerability published on October 21, 2023. stbimage is a single file MIT licensed library for processing images. It may look like stbiloadgifmain doesn’t give guarantees about the content of output value *delays upon failure. Although it sets *delays to zero at the beginning, it doesn’t do it in case the image is not recognized as GIF and a…
When was CVE-2023-45666 disclosed?
CVE-2023-45666 was first published in the National Vulnerability Database on October 21, 2023, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-45666 actively exploited?
CVE-2023-45666 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 40.8% of all scored CVEs.
What is the CVSS score of CVE-2023-45666?
CVE-2023-45666 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2023-45666?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-45666, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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