How severe is CVE-2026-77620?

CVE-2026-77620 has a CVSS 4.0 base score of 8.7, rated high severity.

Is CVE-2026-77620 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-77620?

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-2026-77620 published?

CVE-2026-77620 was published on 2026-09-22 and last updated on 2026-09-24.

CVE-2026-77620

CVE-2026-77620 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. 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-409.

Key facts

Severity: High (CVSS 4.0 base score 8.7)
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-409
Published: 2026-09-22
Last modified: 2026-09-24

Description

Vector is a high-performance observability data pipeline. From 0.15.0 until 0.57.0, the logstash source feeds each decompressed frame back into its decoder without limiting nested compression depth. An unauthenticated remote peer that can reach the default 0.0.0.0:5044 listener can send many nested compressed frames, causing recursive decoding that exhausts the worker thread stack and aborts the process. The same nested construction amplifies decompressed input, and process termination can halt log ingestion for every tenant on a shared pipeline. This issue is fixed in version 0.57.0.

Frequently asked questions

What is CVE-2026-77620?: Vector is a high-performance observability data pipeline. From 0.15.0 until 0.57.0, the logstash source feeds each decompressed frame back into its decoder without limiting nested compression depth. An unauthenticated remote peer that can reach the default 0.0.0.0:5044 listener can send many nested compressed frames, causing recursive decoding that exhausts the worker thread stack and aborts the process. The same nested construction amplifies decompressed input, and process termination can halt log ingestion for every tenant on a shared pipeline. This issue is fixed in version 0.57.0.
How severe is CVE-2026-77620?: CVE-2026-77620 has a CVSS 4.0 base score of 8.7, rated high severity.
Is CVE-2026-77620 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-77620?: 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-2026-77620 published?: CVE-2026-77620 was published on 2026-09-22 and last updated on 2026-09-24.

References

Other CWE-409 vulnerabilities

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CVE-2026-53430 — High (CVSS 8.7): Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in elixir-grpc grpc…
CVE-2026-44697 — High (CVSS 8.6): Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, a remote, unauthenticated…
CVE-2026-94637 — High (CVSS 8.2): Improper handling of highly compressed data (data amplification) vulnerability in Apache Thrift Go bindings. This…

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