Zebra has pre-handshake buffer capacity reservation based on attacker-claimed body length

Exploitation

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

CVSS

3.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Am I affected You are affected if: 1. You run zebrad up to and including v4.4.1. 2. Your node accepts inbound P2P connections (network.listenaddr is set, which is the default). Summary The P2P codec's Codec::decode() method calls src.reserve(bodylen + HEADERLEN) after parsing a 24-byte protocol header, using the attacker-claimed bodylen field. This reserves up to MAXPROTOCOLMESSAGELEN (~2 MiB) of virtual buffer capacity per connection before any body bytes arrive and before the handshake completes. However, BytesMut::reserve() sets virtual capacity without committing physical memory pages. The operating system does not allocate physical RAM until bytes are actually written into the buffer. Since the attacker never sends body bytes, the reserved capacity remains uncommitted. Reproduction of the reporter's PoC (256 threads, 30 seconds of sustained connections) showed negligible RSS impact on the Zebra process. Zebra's existing mitigations further constrain the practical attack surface:…

Published by the source

2 Jul 2026, 19:42 UTC

Last modified by the source

2 Jul 2026, 19:42 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-h72h-ppcx-998p

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-h72h-ppcx-998p

Advisory: Zebra has pre-handshake buffer capacity reservation based on attacker-claimed body length
IDs: GHSA-h72h-ppcx-998p
Record: https://patchnext.com/advisories/ghsa-h72h-ppcx-998p (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: zebra-network 7.0.0; zebrad 4.5.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io zebra-network: affected <= 6.0.0; fixed in 7.0.0
- crates.io zebrad: affected <= 4.4.1; fixed in 4.5.0

## Suggested inspection (read-only)
- crates.io zebra-network: check the installed version with your package manager.
- crates.io zebrad: 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 zebra-network, zebrad.
- 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-h72h-ppcx-998p (GitHub-reviewed advisory GHSA-h72h-ppcx-998p lists affected ranges: crates.io zebra-network >=0 =0 <=4.4.1)

Commands are suggestions: review each one before running it.