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CVE-2026-28449

OpenClaw < 2026.2.25 - Webhook Replay Attack via Missing Durable Replay Suppression

6.3 MediumFix available

OpenClaw versions prior to 2026.2.25 lack durable replay state for Nextcloud Talk webhook events, allowing valid signed webhook requests to be replayed without suppression. Attackers can capture and replay previously valid signed webhook requests to trigger duplicate inbound message processing and cause integrity or availability issues.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
Low

Exploit likelihood

0.28%Up 0.2 points since Mar 19, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.3

OpenClaw < 2026.2.25 - Webhook Replay Attack via Missing Durable Replay Suppression

OpenClaw versions prior to 2026.2.25 lack durable replay state for Nextcloud Talk webhook events, allowing valid signed webhook requests to be replayed without suppression. Attackers can capture and replay previously valid signed webhook requests to trigger duplicate inbound message processing and cause integrity or availability issues.

Record
CVE-2026-28449
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Weakness
CWE-294
Updated
2026-11-02
EUVDEUVD-2026-13011 6.3

OpenClaw versions prior to 2026.2.25 lack durable replay state for Nextcloud Talk webhook events, allowing valid signed webhook requests to be replayed without suppression. Attackers can capture and replay previously valid signed webhook requests to trigger duplicate inbound message processing and cause integrity or availability issues.

Record
EUVD-2026-13011
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-r9q5-c7qc-p26w 5.3

OpenClaw's Nextcloud Talk webhook replay could trigger duplicate inbound processing

Summary

When Nextcloud Talk webhook signing was valid, replayed requests could be accepted without durable replay suppression, allowing duplicate inbound processing after replay-window expiry or process restart.

Details

OpenClaw's Nextcloud Talk webhook path verified HMAC(secret, random + body) but previously lacked durable replay state tied to webhook events. This allowed replay of a previously valid signed request in some operational conditions.

The fix on main adds:

  • persistent per-account replay dedupe for Nextcloud Talk webhook events,
  • replay checks before webhook side effects (onMessage),
  • backend-origin validation against configured account base URL (when configured).

Impact

A captured valid signed webhook request could be replayed to trigger duplicate inbound handling. This is an integrity/availability issue (duplicate actions/noise), scoped to deployments using Nextcloud Talk webhook integration.

Affected Packages / Versions

  • Package: openclaw (npm)
  • Affected: <= 2026.2.24
  • Patched in release: 2026.2.25

Fix Commit(s)

  • d512163d686ad6741783e7119ddb3437f493dbbc

Release Process Note

patched_versions is pre-set to the release (2026.2.25) so once npm release 2026.2.25 is published, advisory is now published.

OpenClaw thanks @aristorechina for reporting.

Record
GHSA-r9q5-c7qc-p26w
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-294
Updated
2026-11-02
NVD 6.3

OpenClaw versions prior to 2026.2.25 lack durable replay state for Nextcloud Talk webhook events, allowing valid signed webhook requests to be replayed without suppression. Attackers can capture and replay previously valid signed webhook requests to trigger duplicate inbound message processing and cause integrity or availability issues.

Record
CVE-2026-28449
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Weakness
CWE-294
Updated
2026-11-02
OSV 6.3

OpenClaw < 2026.2.25 - Webhook Replay Attack via Missing Durable Replay Suppression

OpenClaw versions prior to 2026.2.25 lack durable replay state for Nextcloud Talk webhook events, allowing valid signed webhook requests to be replayed without suppression. Attackers can capture and replay previously valid signed webhook requests to trigger duplicate inbound message processing and cause integrity or availability issues.

Record
CVE-2026-28449
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-294
Updated
2026-11-02
OSVGHSA-r9q5-c7qc-p26w 5.3

OpenClaw's Nextcloud Talk webhook replay could trigger duplicate inbound processing

Summary

When Nextcloud Talk webhook signing was valid, replayed requests could be accepted without durable replay suppression, allowing duplicate inbound processing after replay-window expiry or process restart.

Details

OpenClaw's Nextcloud Talk webhook path verified HMAC(secret, random + body) but previously lacked durable replay state tied to webhook events. This allowed replay of a previously valid signed request in some operational conditions.

The fix on main adds:

  • persistent per-account replay dedupe for Nextcloud Talk webhook events,
  • replay checks before webhook side effects (onMessage),
  • backend-origin validation against configured account base URL (when configured).

Impact

A captured valid signed webhook request could be replayed to trigger duplicate inbound handling. This is an integrity/availability issue (duplicate actions/noise), scoped to deployments using Nextcloud Talk webhook integration.

Affected Packages / Versions

  • Package: openclaw (npm)
  • Affected: <= 2026.2.24
  • Patched in release: 2026.2.25

Fix Commit(s)

  • d512163d686ad6741783e7119ddb3437f493dbbc

Release Process Note

patched_versions is pre-set to the release (2026.2.25) so once npm release 2026.2.25 is published, advisory is now published.

OpenClaw thanks @aristorechina for reporting.

Record
GHSA-r9q5-c7qc-p26w
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-294
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
openclaw
npm
 through 2026.2.24
2026.2.25
openclaw
npm
 before 2026.2.25
2026.2.25

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-28449 is a medium vulnerability (CVSS 6.3) in Openclaw, published March 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.28%, the 21st percentile. Fixed in openclaw 2026.2.25.

References

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