# CVE-2026-77622: Sliver: Unauthenticated Memory Exhaustion Denial of Service in Sliver HTTP(S) Listener PNG Decoder

Status: published. Published: 2026-11-05. Updated: 2026-11-05.

Sliver is a command and control framework. Prior to 1.7.6, an HTTP(S) listener using the PNG encoder accepts attacker-controlled PNG dimensions without an effective decoded-size or pixel limit in util/encoders/images.go, while the listener nonce space implemented in server/encoders/encoders.go is small enough to search remotely. An unauthenticated attacker who identifies a valid nonce can submit a highly compressed image to PNGEncoder.Decode, where it expands during png.Decode, exhausting server memory and causing a complete loss of availability. This vulnerability is fixed in 1.7.6.

## Remediation

- fix: github.com/BishopFox/sliver (Go): OSV reports a fixed version 1.7.6. Check the advisory for supported release branches. (source: OSV GHSA-663m-7x7m-g4fw) — https://github.com/advisories/GHSA-663m-7x7m-g4fw

## Affected products and versions

- BishopFox / sliver: < 1.7.6 (affected). Source: CNA: GitHub_M
-  / github.com/BishopFox/sliver (github.com/BishopFox/sliver): ≥ 0; < 1.7.6 (affected, semver); OSV events: introduced 0; fixed 1.7.6. Source: OSV GHSA-663m-7x7m-g4fw

## Severity and prioritization

- CVSS 4.0: 8.2 (high); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-770

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/BishopFox/sliver/security/advisories/GHSA-663m-7x7m-g4fw (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/BishopFox/sliver/commit/80273462bd8b2a3cd724d2d6d0301a0cabfa977d (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/BishopFox/sliver/releases/tag/v1.7.6 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/advisories/GHSA-663m-7x7m-g4fw (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-663m-7x7m-g4fw (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-77622; retrieved 2026-11-05; source updated 2026-11-05

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-663m-7x7m-g4fw; retrieved 2026-11-05; source updated 2026-10-19

Revision: e8ac2bb8705d0c017141238e4179f4bd019e5f4e0ee70c8e1bccf2683cd73811

Canonical: https://y2.dev/cve/CVE-2026-77622

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