How severe is CVE-2021-45340?

CVE-2021-45340 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-45340 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-45340?

CVE-2021-45340 affects Libsixel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-45340?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-45340 published?

CVE-2021-45340 was published on 2022-01-25 and last updated on 2026-06-17.

CVE-2021-45340

CVE-2021-45340 is a medium-severity vulnerability in Libsixel with a CVSS 3.x base score of 6.5. 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Libsixel
Published: 2022-01-25
Last modified: 2026-06-17

Description

In Libsixel prior to and including v1.10.3, a NULL pointer dereference in the stb_image.h component of libsixel allows attackers to cause a denial of service (DOS) via a crafted PICT file.

Frequently asked questions

What is CVE-2021-45340?: In Libsixel prior to and including v1.10.3, a NULL pointer dereference in the stb_image.h component of libsixel allows attackers to cause a denial of service (DOS) via a crafted PICT file.
How severe is CVE-2021-45340?: CVE-2021-45340 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-45340 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-45340?: CVE-2021-45340 affects Libsixel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-45340?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-45340 published?: CVE-2021-45340 was published on 2022-01-25 and last updated on 2026-06-17.

References

https://github.com/libsixel/libsixel/issues/51

Affected products (1)

cpe:2.3:a:libsixel:libsixel:*:*:*:*:*:*:*:*

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