# CVE-2026-68511: Paaster: TOCTOU race condition defeats the 'burn after reading' guarantee on view-once pastes

Status: published. Published: 2026-11-11. Updated: 2026-11-11.

Paaster is a pastebin application. Prior to version 3.3.0, Paaster's "view once" (burn-after-reading) paste mode can be bypassed with concurrent requests. The check that's supposed to enforce single-use is a plain read followed by a separate write, with no atomicity, so multiple simultaneous requests can all see the paste as "not yet read" and all successfully retrieve it. This issue has been patched in version 3.3.0.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- WardPearce / paaster: < 3.3.0 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-362

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/WardPearce/paaster/security/advisories/GHSA-xh42-5mjw-2f4v (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/WardPearce/paaster/releases/tag/v3.3.0 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-68511; retrieved 2026-11-11; source updated 2026-11-11

Revision: d142760c2b7c1b2d44321c53dd570190671c1b1d05d0bafb3d96fc109b31b78a

Canonical: https://y2.dev/cve/CVE-2026-68511

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