CVE-2026-77622
Sliver: Unauthenticated Memory Exhaustion Denial of Service in Sliver HTTP(S) Listener PNG Decoder
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.
Fixes and workarounds
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-g4fwAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| sliver BishopFox |
< 1.7.6 (affected) | CNA: GitHub_M |
github.com/BishopFox/slivergithub.com/BishopFox/sliver
Go |
≥ 0; < 1.7.6 (affected, semver); OSV events: introduced 0; fixed 1.7.6Source events (semver)Other versions: unaffected |
OSV GHSA-663m-7x7m-g4fw |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 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 | CNA: GitHub_M |
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-g4fwCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/BishopFox/sliver/commit/80273462bd8b2a3cd724d2d6d0301a0cabfa977dCNA: GitHub_M · x_refsource_MISC
- https://github.com/BishopFox/sliver/releases/tag/v1.7.6CNA: GitHub_M · x_refsource_MISC
- https://github.com/advisories/GHSA-663m-7x7m-g4fwOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-663m-7x7m-g4fwOSV / GitHub Security Advisories · osv
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