CVE-2026-42154

Prometheus: remote read endpoint allows denial of service via crafted snappy payload

HIGH
7.5
CVSS Score
Published: May 4, 2026 at 06:13 PM UTC
Updated: September 10, 2026 at 01:20 PM UTC
7 products affected across 2 vendorsPrometheusOpenShift Container PlatformOpenShift AI

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Severity
HIGH7.5
Exploit prediction
EPSS 0.8%
SSVC
No known exploit

Description

Prometheus is an open-source monitoring system and time series database. Prior to versions 3.5.3 and 3.11.3, the remote read endpoint (/api/v1/read) does not validate the declared decoded length in a snappy-compressed request body before allocating memory. An unauthenticated attacker can send a small payload that causes a huge heap allocation per request. Under concurrent load this can exhaust available memory and crash the Prometheus process. This issue has been patched in versions 3.5.3 and 3.11.3.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.11.3v < 3.5.33.6.0 ≤ v < 3.11.3
Affected range stops below 3.11.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.5.3, so it looks safe — our inference, not a vendor statement
All versions
Vendor states this is fixed in 1782859326 (unaffected)
Vendor states this is fixed in 1784053555 (unaffected)
Vendor states this is fixed in 1784349713 (unaffected)
Vendor states this is fixed in 1784583836 (unaffected)
Vendor states this is fixed in 1784828871 (unaffected)
Vendor states this is fixed in 1785360067 (unaffected)
Vendor states this is fixed in 1785582559 (unaffected)
Vendor states this is fixed in 1786998274 (unaffected)
Vendor states this is fixed in 1786999821 (unaffected)
Vendor states this is fixed in 1787343838 (unaffected)
Vendor states this is fixed in 4 (unaffected)
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (52)

x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/prometheus/prometheus/pull/18584
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/prometheus/prometheus/pull/18585
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/prometheus/prometheus/releases/tag/v3.11.3
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/prometheus/prometheus/releases/tag/v3.5.3
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:25039
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:25245
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:29770

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400CWE-789CWE-770

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