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Full vulnerability report · 2026
CVE-2026-1584High confidence

Gnutls: gnutls: remote denial of service via crafted clienthello with invalid psk binder

Unknown · Unknown

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-1584 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitygnutls: gnutls: Remote Denial of Service via crafted ClientHello with invalid PSK binder
4 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • gnutls-main@aarch64 as a component of Red Hat Hardened Images
  • gnutls-main@noarch as a component of Red Hat Hardened Images
  • gnutls-main@src as a component of Red Hat Hardened Images
  • gnutls-main@x86_64 as a component of Red Hat Hardened Images
Summary
A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-20986

No EUVD known-exploited evidence

A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.

What

A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → NULL Pointer Dereference → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-476 ↗

CWE-476: NULL Pointer Dereference. The product dereferences a pointer that it expects to be valid but is NULL.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-476
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-20986Official EUVD mapping

A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.

Official EUVD record ↗
BSI · German · WID-SEC-2026-0359GnuTLS: Mehrere Schwachstellen ermöglichen Denial of Service

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in GnuTLS ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260415Security Bulletin 15 April 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 15 April 2026, published on 15 April 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0627Multiples vulnérabilités dans les produits Splunk

.cve.org/CVERecord?id=CVE-2025-8291 Référence CVE CVE-2025-9086 https://www.cve.org/CVERecord?id=CVE-2025-9086 Référence CVE CVE-2025-9232 https://www.cve.org/CVERecord?id=CVE-2025-9232 Référence CVE CVE-2025-9820 https://www.cve.org/CVERecord?id=CVE-2025-9820 Référence CVE CVE-2026-0865 https://www.cve.org/CVERecord?id=CVE-2026-0865 Référence CVE CVE-2026-0965 https://www.cve.org/CVERecord?id=CVE-2026-0965 Référence CVE CVE-2026-0967 https://www.cve.org/CVERecord?id=CVE-2026-0967 Référence CVE CVE-2026-0968 https://www.cve.org/CVERecord?id=CVE-2026-0968 Référence CVE CVE-2026-1225 https://www.cve.org/CVERecord?id=CVE-2026-1225 Référence CVE CVE-2026-1584 https://www.cve.org/CVERecord?id=CVE-2026-1584 Référence CVE CVE-2026-1605 https://www.cve.org/CVERecord?id=CVE-2026-1605 Référence CVE CVE-2026-1861 https://www.cve.org/CVERecord?id=CVE-2026-1861 Référence CVE CVE-2026-20238 https://www.cve.org/CVERecord?id=CVE-2026-20238 Référence CVE CVE-2026-20239 https://www.cve.org/CVERecord?id=CVE-2026-20239 Référence CVE CVE-2026-20240 https://www.cve.org/CVERecord?id=CVE-2026-20240 Référence CVE CVE-2026-21441 https://www.cve.org/CVERecord?id=CVE-2026-21441 Référence CVE CVE-2026-21637 https://www.cve.org/CVERecord?id=CVE-2026-21637 Référence CVE CVE-2026-21710 https://www.cve.org/CVERecord?id=CVE-2

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0137Multiples vulnérabilités dans GnuTLS

De multiples vulnérabilités ont été découvertes dans GnuTLS. Elles permettent à un attaquant de provoquer un déni de service à distance.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-012167GNU Project等の複数ベンダの製品におけるNULL ポインタデリファレンスに関する脆弱性

gnutlsに脆弱性が発見されました。リモートの認証されていない攻撃者がTLSハンドシェイク中に無効な事前共有鍵（PSK）バインダー値を含む特別に細工されたClientHelloメッセージを送信することで、この脆弱性を悪用できます。これによりNULLポインタの参照が発生し、サーバーがクラッシュしてリモートからのサービス拒否（DoS）状態を引き起こす可能性があります。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
version range in vendor record
Fixed
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 9 Apr 2026 · Last source change 24 Aug 2026, 12:06 UTC · CWE-476 · NULL Pointer Dereference

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-20986
Product sourceCNA
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    version range in vendor record · Fixed: 3.8.12-1.1.hum1 < *
    After
    version range in vendor record · Fixed: Red Hat Hardened Images: 3.8.12-1.1.hum1 < *
    CNA ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: 3.8.12-1.1.hum1 < *
    After
    version range in vendor record · Fixed: 3.8.12-1.1.hum1 < *
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-20986↗Vendor advisory↗Vendor advisory↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-1584 · cve.blacktree.nl