Client crash via unbounded SSE buffering
Published Nov 1, 2026 · Updated Nov 1, 2026
Memory exhaustion in the AG-UI SSE parser 0.0.58 and earlier allows remote attackers to crash clients via crafted responses. The parseSSEStream function appends decoded chunks to an uncapped string and releases the retained tail only when a double-newline event boundary arrives. Exploitation requires control of an agent response consumed by @ag-ui/client; the reported consequence is memory exhaustion rather than data access.
Summary
What happened
Memory exhaustion in the AG-UI SSE parser 0.0.58 and earlier allows remote attackers to crash clients via crafted responses. The parseSSEStream function appends decoded chunks to an uncapped string and releases the retained tail only when a double-newline event boundary arrives. Exploitation requires control of an agent response consumed by @ag-ui/client; the reported consequence is memory exhaustion rather than data access.
The record
- CVE
- CVE-2026-120235
- Published
- Nov 1, 2026
- Updated
- Nov 1, 2026
- Vendor
- AG-UI Protocol
- Product
- AG-UI
- Classifications
- CWE-400, CWE-404, T1499.003
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- Nov 1, 2026CVE publishedPublication date reported by the CVE source.
- Nov 1, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.0.1
- Affected versionversion=0.0.10
- Affected versionversion=0.0.11
- Affected versionversion=0.0.12
- Affected versionversion=0.0.13
- Affected versionversion=0.0.14
- Affected versionversion=0.0.15
- Affected versionversion=0.0.16
- Affected versionversion=0.0.17
- Affected versionversion=0.0.18
- Affected versionversion=0.0.19
- Affected versionversion=0.0.2
- Affected versionversion=0.0.20
- Affected versionversion=0.0.21
- Affected versionversion=0.0.22
- Affected versionversion=0.0.23
- Affected versionversion=0.0.24
- Affected versionversion=0.0.25
- Affected versionversion=0.0.26
- Affected versionversion=0.0.27
- Affected versionversion=0.0.28
- Affected versionversion=0.0.29
- Affected versionversion=0.0.3
- Affected versionversion=0.0.30
- Affected versionversion=0.0.31
- Affected versionversion=0.0.32
- Affected versionversion=0.0.33
- Affected versionversion=0.0.34
- Affected versionversion=0.0.35
- Affected versionversion=0.0.36
- Affected versionversion=0.0.37
- Affected versionversion=0.0.38
- Affected versionversion=0.0.39
- Affected versionversion=0.0.4
- Affected versionversion=0.0.40
- Affected versionversion=0.0.41
- Affected versionversion=0.0.42
- Affected versionversion=0.0.43
- Affected versionversion=0.0.44
- Affected versionversion=0.0.45
- Affected versionversion=0.0.46
- Affected versionversion=0.0.47
- Affected versionversion=0.0.48
- Affected versionversion=0.0.49
- Affected versionversion=0.0.5
- Affected versionversion=0.0.50
- Affected versionversion=0.0.51
- Affected versionversion=0.0.52
- Affected versionversion=0.0.53
- Affected versionversion=0.0.54
- Affected versionversion=0.0.55
- Affected versionversion=0.0.56
- Affected versionversion=0.0.57
- Affected versionversion=0.0.58
- Affected versionversion=0.0.6
- Affected versionversion=0.0.7
- Affected versionversion=0.0.8
- Affected versionversion=0.0.9
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- Boundary-less SSE response memory-exhaustion PoCproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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