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High, CVSS 7.1

Sliver: Nil Pointer Dereference in tunnelCloseHandler causes panic when a reverse tunnel (rportfwd) close is attempted

GHSA-c279-989m-238f

What to do

Vendor response not established. Follow the primary source's mitigation guidance and check back for a fix.

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

  • Go github.com/bishopfox/sliver

    Affected
    <= 1.7.3
    Fixed in
    no fixed version recorded

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
7.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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 A nil pointer dereference in tunnelCloseHandler causes the handler goroutine to panic whenever a reverse tunnel (rportfwd) close is attempted. Both the legitimate close path AND the unauthorized close path dereference tunnel.SessionID where tunnel is guaranteed nil. This means rportfwd tunnels can never be cleanly closed, and any authenticated implant can trigger repeated goroutine panics. Details File: server/handlers/sessions.go lines 172 and 175 The function enters an else block precisely because core.Tunnels.Get(tunnelData.TunnelID) returned nil. Both conditions inside that else block then dereference tunnel.SessionID instead of rtunnel.SessionID: Note: The identical bug was already fixed in tunnelDataHandler at lines 124/126 (correctly uses rtunnel.SessionID), but the fix was not applied to tunnelCloseHandler. PoC Confirmed on master commit 7ac4db3fa with standalone reproducer. Output: Impact - rportfwd tunnels cannot be closed — functional regression - Any authenticated…

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

    Published from ghsa record GHSA-c279-989m-238f

Agent brief

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# Patch Next advisory brief: GHSA-c279-989m-238f

Advisory: Sliver: Nil Pointer Dereference in tunnelCloseHandler causes panic when a reverse tunnel (rportfwd) close is attempted
IDs: GHSA-c279-989m-238f
Record: https://patchnext.com/advisories/ghsa-c279-989m-238f (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/bishopfox/sliver: affected <= 1.7.3

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

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on 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://github.com/advisories/GHSA-c279-989m-238f (GitHub-reviewed advisory GHSA-c279-989m-238f lists affected ranges: Go github.com/bishopfox/sliver >=0 <=1.7.3)

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