Sliver Vulnerable to Authenticated OOM via Memory Exhaustion in mTLS/WireGuard Transports

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.7 · 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/E:P · score source

EPSS

• CVE-2026-32941: 0.31% estimated exploitation activity in the next 30 days; percentile 23.92 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A Remote OOM (Out-of-Memory) vulnerability exists in the Sliver C2 server's mTLS and WireGuard C2 transport layer. The socketReadEnvelope and socketWGReadEnvelope functions trust an attacker-controlled 4-byte length prefix to allocate memory, with ServerMaxMessageSize allowing single allocations of up to ~2 GiB. A compromised implant or an attacker with valid credentials can exploit this by sending fabricated length prefixes over concurrent yamux streams (up to 128 per connection), forcing the server to attempt allocating ~256 GiB of memory and triggering an OS OOM kill. This crashes the Sliver server, disrupts all active implant sessions, and may degrade or kill other processes sharing the same host. The same pattern also affects all implant-side readers, which have no upper-bound check at all. --- Root Cause Analysis The C2 envelope framing protocol uses a 4-byte little-endian length prefix to delimit protobuf messages on the wire: In socketReadEnvelope, after reading the…

Published by the source

17 Mar 2026, 17:48 UTC

Last modified by the source

20 Mar 2026, 21:21 UTC

Source last checked

26 Oct 2026, 15:18 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-97vp-pwqj-46qc

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# Patch Next advisory brief: CVE-2026-32941

Advisory: Sliver Vulnerable to Authenticated OOM via Memory Exhaustion in mTLS/WireGuard Transports
IDs: CVE-2026-32941, GHSA-97vp-pwqj-46qc
Record: https://patchnext.com/advisories/cve-2026-32941 (revision 1, source checked 26 Oct 2026, 15:18 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.7)
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-97vp-pwqj-46qc (GitHub-reviewed advisory GHSA-97vp-pwqj-46qc lists affected ranges: Go github.com/bishopfox/sliver >=0 <=1.7.3)

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