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CVE Record

CVE-2026-42154: Prometheus: remote read endpoint allows denial of service via crafted snappy payload

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.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Prometheus can be crashed by a small crafted request to its remote read API. The request can trigger a very large memory allocation, causing the monitoring service to run out of memory under load. This is an availability risk, not a data theft issue, based on the supplied CVSS details.

Executive priority

Treat as a prompt availability fix for monitoring infrastructure. A crash in Prometheus can reduce visibility during incidents, even though the cited evidence does not indicate confidentiality or integrity impact.

Technical view

Before Prometheus 3.5.3 and 3.11.3, /api/v1/read fails to validate the declared decoded length of a snappy-compressed request before memory allocation. A network attacker with access to the endpoint can cause excessive heap allocation per request, potentially crashing the process. The issue maps to uncontrolled resource consumption and excessive allocation weaknesses.

Likely exposure

Exposure is likely where Prometheus versions below 3.5.3, or 3.6.0 through below 3.11.3, have /api/v1/read reachable from untrusted networks. Red Hat advisories indicate downstream package impact should also be checked for Red Hat-managed environments.

Exploitation context

The bundle states unauthenticated network exploitation is possible and CVSS rates attack complexity low. It does not cite known public exploitation, and KEV is false, so active exploitation should not be assumed from this evidence.

Researcher notes

Focus review on remote read exposure, snappy request length validation, and memory allocation behavior. The supplied sources identify fixes in Prometheus 3.5.3 and 3.11.3, plus Red Hat downstream advisories. Evidence is sufficient for remediation direction but not for claiming active exploitation.

Mitigation direction

  • Upgrade Prometheus to 3.5.3 or 3.11.3 as applicable.
  • Apply relevant Red Hat errata for Red Hat packaged deployments.
  • Restrict access to /api/v1/read to trusted clients only.
  • Check vendor guidance for any deployment-specific compensating controls.

Validation and detection

  • Inventory Prometheus versions across production and staging environments.
  • Confirm whether /api/v1/read is reachable from untrusted networks.
  • Review crash, restart, and out-of-memory events around Prometheus processes.
  • Verify patched versions or vendor-fixed packages after remediation.
Prepared
Confidence
high
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-400: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cwe · low confidence lookup

CWE-770: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cwe · low confidence lookup

CWE-789: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Database behavior lookup

The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-42154 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
18Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6GitHub_M
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-42154Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPgithub.com/prometheus/prometheus: Prometheus: Denial of Service via uncontrolled memory allocation in remote read endpoint
other:Red Hat severity ratingcvssV3_1
  • 2026-05-04T19:02:19.626Z: Reported to Red Hat.
  • 2026-05-04T18:13:12.340Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
prometheusprometheus< 3.5.3, >= 3.6.0, < 3.11.3Listed
Weakness

CWE details

CWE-400CWE-770CWE-789

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-400 · source CWE mapping

Uncontrolled Resource Consumption

Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-770 · source CWE mapping

Allocation of Resources Without Limits or Throttling

Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-789 · source CWE mapping

Memory Allocation with Excessive Size Value

Memory Allocation with Excessive Size Value represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs