WeeChat (Wee Enhanced Environment for Chat) is a free chat client. In versions 4.3.0 through 4.9.0, the WeeChat relay module's WebSocket permessage-deflate decompression function relay_websocket_inflate() has no upper bound on output size. An authenticated relay user can send a small compressed WebSocket frame (~100 bytes) that decompresses to gigabytes, exhausting all server memory and crashing the entire WeeChat process. The api protocol enables permessage-deflate and requires authentication before WebSocket upgrade. Version 4.9.1 patches the issue.
CVE-2026-53524
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 82% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EG Risk
- 45(Track)EG Risk 45/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation40% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 18%
- KEV
- Not listed
Published
August 21, 2026
Last Modified
August 24, 2026
Advisory Details (1)
Auto-updated Aug 21, 2026Decompression Bomb in Relay WebSocket (DoS) · Advisory · weechat/weechat · GitHub
https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 9× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-25 20:37 UTCEG score recompute
- 2026-08-25 13:49 UTCEPSS rescore
- 2026-08-24 20:27 UTCEG score recompute
- 2026-08-24 20:12 UTCEG score recompute
- 2026-08-23 23:39 UTCEG score recompute
- 2026-08-23 00:19 UTCEPSS rescore
- 2026-08-21 23:26 UTCEG score recompute
- 2026-08-21 22:29 UTCEG score recompute
- 2026-08-21 22:29 UTCMITRE cvelistV5first tracked
Frequently asked(5)
What is CVE-2026-53524?
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-53524
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