How severe is CVE-2021-42716?

CVE-2021-42716 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2021-42716 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-42716?

CVE-2021-42716 primarily affects Nothings Stb Image.h. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-42716?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-42716 published?

CVE-2021-42716 was published on 2021-10-21 and last updated on 2026-06-17.

CVE-2021-42716

CVE-2021-42716 is a high-severity vulnerability in Nothings Stb Image.h with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: High (CVSS 3.x base score 7.1)
CVSS v2: 5.8
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Nothings Stb Image.h
Published: 2021-10-21
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-42716?: 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.
How severe is CVE-2021-42716?: CVE-2021-42716 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2021-42716 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-42716?: CVE-2021-42716 primarily affects Nothings Stb Image.h. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-42716?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-42716 published?: CVE-2021-42716 was published on 2021-10-21 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:nothings:stb_image.h:2.27:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

More vulnerabilities in Nothings Stb Image.h

CVE-2022-28042 — High (CVSS 8.8): stb_image.h v2.27 was discovered to contain an heap-based use-after-free via the function stbi__jpeg_huff_decode.
CVE-2019-19777 — High (CVSS 8.8): stb_image.h (aka the stb image loader) 2.23, as used in libsixel and other products, has a heap-based buffer over-read…
CVE-2018-16981 — High (CVSS 8.8): stb stb_image.h 2.19, as used in catimg, Emscripten, and other products, has a heap-based buffer overflow in the…
CVE-2023-45666 — High (CVSS 7.3): stb_image is a single file MIT licensed library for processing images. It may look like `stbi__load_gif_main`…
CVE-2023-45664 — High (CVSS 7.3): stb_image is a single file MIT licensed library for processing images. A crafted image file can trigger…
CVE-2023-43281 — Medium (CVSS 6.5): Double Free vulnerability in Nothings Stb Image.h v.2.28 allows a remote attacker to cause a denial of service via a…

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