block_buffer: panic corrupts inline buffer position

Exploitation

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

CVSS 4.0

6.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary A caught panic may leave the cursor position of `EagerBuffer` or `ReadBuffer` in a corrupted state; this in turn allows out-of-bounds reads/writes.

Details & PoC The following two tests fail miri: ```rust #[cfg(miri)] #[test] fn eager_digest_blocks_panic_corrupts_inline_position() { // `EagerBuffer` stores its cursor in the last byte of the internal block. // When `digest_blocks` completes a previously partial block, it overwrites // that byte with input data before invoking the caller-provided `compress` // callback. If the callback panics, safe code can catch the panic and keep // using the buffer while its cursor byte no longer satisfies the internal // `pos ::new(&[1, 2]); let _ = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| { buf.digest_blocks(&[3, 0xff], |_| panic!("simulated compression failure")); })); let _ = buf.get_pos(); } #[cfg(miri)] #[test] fn read_buffer_generator_panic_corrupts_inline_position() { // `ReadBuffer` stores its cursor in…

Published by the source

19 Aug 2026, 19:15 UTC

Last modified by the source

30 Oct 2026, 15:45 UTC

Source last checked

31 Oct 2026, 06:45 UTC

1. Revision 5 · amended · 31 Oct 2026

   Amended from osv record GHSA-qwgh-2vcv-g2f7

2. Revision 4 · amended · 30 Oct 2026

   Amended from ghsa record GHSA-qwgh-2vcv-g2f7

3. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-qwgh-2vcv-g2f7

4. Revision 2 · amended · 25 Oct 2026

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

5. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-qwgh-2vcv-g2f7

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# Patch Next advisory brief: GHSA-qwgh-2vcv-g2f7

Advisory: block_buffer: panic corrupts inline buffer position
IDs: GHSA-qwgh-2vcv-g2f7
Record: https://patchnext.com/advisories/ghsa-qwgh-2vcv-g2f7 (revision 5, source checked 31 Oct 2026, 06:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: block_buffer 0.12.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io block_buffer: affected >= 0.11.0, < 0.12.1; fixed in 0.12.1

## Suggested inspection (read-only)
- crates.io block_buffer: 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 block_buffer.
- 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/GHSA-qwgh-2vcv-g2f7 (OSV record GHSA-qwgh-2vcv-g2f7 lists affected ranges: crates.io block_buffer >=0 <0.12.1 (fixed))
- Verified: https://github.com/advisories/GHSA-qwgh-2vcv-g2f7 (GitHub-reviewed advisory GHSA-qwgh-2vcv-g2f7 lists affected ranges: crates.io block_buffer >=0 <0.12.1)
- Verified: https://github.com/advisories/GHSA-qwgh-2vcv-g2f7 (GitHub-reviewed advisory GHSA-qwgh-2vcv-g2f7 lists affected ranges: crates.io block_buffer >=0.11.0 <0.12.1)
- Verified: https://osv.dev/vulnerability/GHSA-qwgh-2vcv-g2f7 (OSV record GHSA-qwgh-2vcv-g2f7 lists affected ranges: crates.io block_buffer >=0.11.0 <0.12.1 (fixed))

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