How severe is CVE-2026-48977?

CVE-2026-48977 has a CVSS 4.0 base score of 7.7, rated high severity.

Is CVE-2026-48977 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-48977?

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-2026-48977 published?

CVE-2026-48977 was published on 2026-09-17 and last updated on 2026-09-23.

CVE-2026-48977

CVE-2026-48977 is a high-severity vulnerability with a CVSS 4.0 base score of 7.7. 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-123.

Key facts

Severity: High (CVSS 4.0 base score 7.7)
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-123
Published: 2026-09-17
Last modified: 2026-09-23

Description

OpenSlide is a C library for reading whole slide image files. From 3.4.1 until 4.0.1, OpenSlide's parse_level0_xml() processing in src/openslide-vendor-ventana.c accepts nonpositive row or column tile counts from a crafted Ventana BIF file. The invalid counts produce attacker-controlled relative memory offsets and allow arbitrary values to be written at those offsets, affecting all supported platforms and configurations and resulting in a crash or potential arbitrary code execution. This issue is fixed in version 4.0.1.

Frequently asked questions

What is CVE-2026-48977?: OpenSlide is a C library for reading whole slide image files. From 3.4.1 until 4.0.1, OpenSlide's parse_level0_xml() processing in src/openslide-vendor-ventana.c accepts nonpositive row or column tile counts from a crafted Ventana BIF file. The invalid counts produce attacker-controlled relative memory offsets and allow arbitrary values to be written at those offsets, affecting all supported platforms and configurations and resulting in a crash or potential arbitrary code execution. This issue is fixed in version 4.0.1.
How severe is CVE-2026-48977?: CVE-2026-48977 has a CVSS 4.0 base score of 7.7, rated high severity.
Is CVE-2026-48977 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-48977?: 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-2026-48977 published?: CVE-2026-48977 was published on 2026-09-17 and last updated on 2026-09-23.

References

Other CWE-123 vulnerabilities

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