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High, CVSS 8.2amended

Sliver: Unauthenticated Memory Exhaustion Denial of Service in Sliver HTTP(S) Listener PNG Decoder

CVE-2026-77622GHSA-663m-7x7m-g4fw

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (github.com/bishopfox/sliver 1.7.6; github.com/BishopFox/sliver 1.7.6), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.2 · 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 · score source
EPSS
No dated EPSS signal available.
Source description

As published by the source; long descriptions are shortened.

Summary Sliver is vulnerable to a Denial of Service (DOS) attack because there is no cap in the size of a PNG file that can be sent to an open http listener and there is a small amount of possible nonces. This vulnerability lets the attacker completely max out the RAM of the machine running server, leading to a complete loss of availability. Details The first vulnerability is that the amount of possible nonces is 65,537. This is found in server/encoders/encoders.go The second vulnerability is there is no limit to how many pixels the PNG encoder will accept from an unauthenticated user. This is found in: util/encoders/images.go PoC The first step to reproduce this vulnerability is building a docker container to make sure no harm is caused. Get the latest version of Sliver (Currently 1.7.3) Build the Docker container: Run the Docker container with a memory cap for example 4GB: After the Docker container starts, create an http listener on port 8080: In a seperate terminal create the…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 4 · amended ·

    Amended from ghsa record GHSA-663m-7x7m-g4fw

  2. Revision 3 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 2 · amended ·

    Amended from osv record GO-2026-6777

  4. Revision 1 · created ·

    Published from osv record GHSA-663m-7x7m-g4fw

Agent brief

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# Patch Next advisory brief: CVE-2026-77622

Advisory: Sliver: Unauthenticated Memory Exhaustion Denial of Service in Sliver HTTP(S) Listener PNG Decoder
IDs: CVE-2026-77622, GHSA-663m-7x7m-g4fw
Record: https://patchnext.com/advisories/cve-2026-77622 (revision 4, source checked 26 Oct 2026, 15:32 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/bishopfox/sliver 1.7.6; github.com/BishopFox/sliver 1.7.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/bishopfox/sliver: affected < 1.7.6; fixed in 1.7.6
- Go github.com/BishopFox/sliver: affected < 1.7.6; fixed in 1.7.6

## Suggested inspection (read-only)
- Go github.com/bishopfox/sliver: check the installed version with your package manager.
- Go github.com/BishopFox/sliver: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/bishopfox/sliver, github.com/BishopFox/sliver.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GO-2026-6777 (OSV record GO-2026-6777 lists affected ranges: Go github.com/bishopfox/sliver >=0 <1.7.6 (fixed))
- Verified: https://osv.dev/vulnerability/GHSA-663m-7x7m-g4fw (OSV record GHSA-663m-7x7m-g4fw lists affected ranges: Go github.com/BishopFox/sliver >=0 <1.7.6 (fixed))
- Verified: https://github.com/advisories/GHSA-663m-7x7m-g4fw (GitHub-reviewed advisory GHSA-663m-7x7m-g4fw lists affected ranges: Go github.com/BishopFox/sliver >=0 <1.7.6)

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