CVE-2026-27571

highPriorität · verfolgen · 30EPSS 0.005 · 45. PerzentilDEEUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.54% (45th) EPSS
CVSS 7.5 · high
Is it mine?
14 products
Prüfe deine Angriffsfläche
Who says so?
5 sources
cnnvd · enisa_euvd · osv · cert_bund

EPSS · bewertet 2026-10-27

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The WebSockets handling of NATS messages handles compressed messages via the WebSockets negotiated compression. Prior to versions 2.11.2 and 2.12.3, the implementation bound the memory size of a NATS message but did not independently bound the memory consumption of the memory stream when constructing a NATS message which might then fail validation for size reasons. An attacker can use a compression bomb to cause excessive memory consumption, often resulting in the operating system terminating the server process. The use of compression is negotiated before authentication, so this does not require valid NATS credentials to exploit. The fix, present in versions 2.11.2 and 2.12.3, was to bounds the decompression to fail once the message was too large, instead of continuing on. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points.

01

cvss

Technischer Schweregrad, 0–10. Eine Zeile je Quelle.

7.5
010

Basiswert 0–10 · höher = schwerwiegender · Vektor überfahren zum Auflösen⚠ Quellen uneinig · medium–high · 5.9–7.5

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USAusnutzbarkeit 3.9 · Auswirkung 3.6
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · security-advisories@github.comAusnutzbarkeit 2.2 · Auswirkung 3.6
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · OSV
v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
02

SSVC

Eine Handlungsentscheidung — aus Ausnutzung und Auswirkung.

Trackcoordinatorcisa_ssvcUS
03

schwächen

Die CWE-Schwächeklassen, zu denen dies gehört.

CWE-409USCWE-409USCWE-770USCWE-770US
04

betroffene Produkte (14)

Betroffene Produkte und Versionsbereiche.

05

Advisories (4)

Hersteller- und Ökosystem-Meldungen dazu.

  • WID-SEC-W-2026-0487NATS Server: Schwachstelle ermöglicht Denial of ServiceDeutsch2026-02-23csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann eine Schwachstelle in NATS Server ausnutzen, um einen Denial of Service Angriff durchzuführen.

  • GHSA-qrvq-68c2-7grwnats-server websockets are vulnerable to pre-auth memory DoS2026-02-24ghsa · osvUS

    ### Impact The WebSockets handling of NATS messages handles compressed messages via the WebSockets negotiated compression. The implementation bound the memory size of a NATS message but did not independently bound the memory consumption of the memory stream when constructing a NATS message which might then fail validation for size reasons. An attacker can use a compression bomb to cause excessive memory consumption, often resulting in the operating system terminating the server process. The use of compression is negotiated before authentication, so this does not require valid NATS credentials to exploit. The fix was to bounds the decompression to fail once the message was too large, instead of continuing on. ### Patches This was released in nats-server without being highlighted as a security issue. It should have been, this was an oversight. Per the NATS security policy, because this does not require a valid user, it is CVE-worthy. This was fixed in the v2.11 series with v2.11.12 and in the v2.12 series with v2.12.3. ### Workarounds This only affects deployments which use WebSockets and which expose the network port to untrusted end-points. ### References This was reported to the NATS maintainers by Pavel Kohout of Aisle Research (www.aisle.com).

  • BIT-nats-2026-27571nats-server websockets are vulnerable to pre-auth memory DoS2026-03-02vendor · osvUS

    NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The WebSockets handling of NATS messages handles compressed messages via the WebSockets negotiated compression. Prior to versions 2.11.2 and 2.12.3, the implementation bound the memory size of a NATS message but did not independently bound the memory consumption of the memory stream when constructing a NATS message which might then fail validation for size reasons. An attacker can use a compression bomb to cause excessive memory consumption, often resulting in the operating system terminating the server process. The use of compression is negotiated before authentication, so this does not require valid NATS credentials to exploit. The fix, present in versions 2.11.2 and 2.12.3, was to bounds the decompression to fail once the message was too large, instead of continuing on. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points.

  • GO-2026-4533nats-server websockets are vulnerable to pre-auth memory DoS in github.com/nats-io/nats-server2026-02-25vendor · osvUS

    nats-server websockets are vulnerable to pre-auth memory DoS in github.com/nats-io/nats-server

06

auch bekannt als (6)

Weitere Namen und Kennungen dieser Entität.

07

quellen

Welche Quellen diesen Datensatz belegen und wann.

cnnvdenisa_euvdosvcert_bundnvdNVDCVE.orgMITRE
veröffentlicht 2026-02-24geändert 2026-06-17
08

Referenzen (13)

Externe Belege — Patches, Meldungen, Analysen.

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