How severe is CVE-2026-54580?

CVE-2026-54580 has a CVSS 4.0 base score of 8.3, rated high severity.

Is CVE-2026-54580 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-54580?

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-2026-54580 published?

CVE-2026-54580 was published on 2026-09-17 and last updated on 2026-09-24.

CVE-2026-54580

CVE-2026-54580 is a high-severity vulnerability with a CVSS 4.0 base score of 8.3. 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-354.

Key facts

Severity: High (CVSS 4.0 base score 8.3)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-354
Published: 2026-09-17
Last modified: 2026-09-24

Description

mport is the MidnightBSD Package Manager. Prior to 2.7.8, libmport/util.c did not make every truncated, corrupt, or failed zstd stream fatal in mport_decompress_zstd(), and libmport/fetch.c did not consistently propagate those failures to index-fetch callers. A malicious or faulty mirror could supply compressed package index data that caused ZSTD_decompressStream() or an output write to fail while leaving partial index output available for later use, resulting in package-index integrity loss or denial of service. This issue is fixed in version 2.7.8.

Frequently asked questions

What is CVE-2026-54580?: mport is the MidnightBSD Package Manager. Prior to 2.7.8, libmport/util.c did not make every truncated, corrupt, or failed zstd stream fatal in mport_decompress_zstd(), and libmport/fetch.c did not consistently propagate those failures to index-fetch callers. A malicious or faulty mirror could supply compressed package index data that caused ZSTD_decompressStream() or an output write to fail while leaving partial index output available for later use, resulting in package-index integrity loss or denial of service. This issue is fixed in version 2.7.8.
How severe is CVE-2026-54580?: CVE-2026-54580 has a CVSS 4.0 base score of 8.3, rated high severity.
Is CVE-2026-54580 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-54580?: 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-2026-54580 published?: CVE-2026-54580 was published on 2026-09-17 and last updated on 2026-09-24.

References

Other CWE-354 vulnerabilities

CVE-2025-11543 — Critical (CVSS 9.8): Improper Validation of Integrity Check Value vulnerability in Sharp Display Solutions projectors allows a attacker may…
CVE-2024-25678 — Critical (CVSS 9.8): In LiteSpeed QUIC (LSQUIC) Library before 4.0.4, DCID validation is mishandled.
CVE-2023-33668 — Critical (CVSS 9.8): DigiExam up to v14.0.2 lacks integrity checks for native modules, allowing attackers to access PII and takeover…
CVE-2017-15994 — Critical (CVSS 9.8): rsync 3.1.3-development before 2017-10-24 mishandles archaic checksums, which makes it easier for remote attackers to…
CVE-2026-75803 — Critical (CVSS 9.1): Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty ciphertext can report success without verifying…
CVE-2026-49230 — Critical (CVSS 9.1): Improper Validation of Integrity Check Value vulnerability in Apache APISIX. The jwe-decrypt plugin under default…

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