CVE-2026-83530Network attack vector

Availability degradation via pre-limit rune-buffer allocation

Published Sep 9, 2026 · Updated Sep 9, 2026

Uncontrolled memory allocation in cel-go before 0.29.0 allows remote attackers to degrade service availability with oversized CEL expressions. Env.Compile and Env.Parse pass the full expression to common.NewTextSource, whose rune buffer reserves input-proportional memory before ParserExpressionSizeLimit is enforced. Exposure requires an embedding application to accept attacker-supplied CEL expressions with that limit configured; the resulting allocation and garbage-collection pressure affect availability without reported data access or modification.

CVSS severity6.9
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled memory allocation in cel-go before 0.29.0 allows remote attackers to degrade service availability with oversized CEL expressions. Env.Compile and Env.Parse pass the full expression to common.NewTextSource, whose rune buffer reserves input-proportional memory before ParserExpressionSizeLimit is enforced. Exposure requires an embedding application to accept attacker-supplied CEL expressions with that limit configured; the resulting allocation and garbage-collection pressure affect availability without reported data access or modification.

The record

CVE
CVE-2026-83530
Published
Sep 9, 2026
Updated
Sep 9, 2026
Vendor
Google Cloud
Product
cel-go
Classifications
CWE-789, CAPEC-130, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 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.

  1. Affected versionversion=0 <0.29.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google Cloud · cel-goversion=0 <0.29.0

Published CVSS scores

6.9GoogleCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
CAPEC-130Excessive Allocation
T1499.003Endpoint Denial of Service: Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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