EUVD-2026-33755
GHSA-6452-5wg5-m56r
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Lifecycle Timeline
2DescriptionCVE.org
A flaw was found in gnutls. The PKCS#7 padding check, performed during decryption, was not constant-time. This timing side-channel could allow a remote attacker to potentially leak sensitive information about the padding bytes through observable timing differences. This vulnerability is a form of information disclosure.
AnalysisAI
GnuTLS's PKCS#7 padding validation during decryption is not implemented as a constant-time operation, creating a timing side-channel (CWE-208) that remote unauthenticated attackers can exploit to infer padding byte values on CBC-mode cipher suites. Affected deployments include GnuTLS as packaged across Red Hat Enterprise Linux 6 through 10, Red Hat Hardened Images, and Red Hat OpenShift Container Platform 4. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The target service must be running a GnuTLS-backed TLS implementation configured to use CBC-mode cipher suites that employ PKCS#7 padding (e.g., AES-128-CBC or AES-256-CBC cipher suites). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS score of 3.7 (Low) with vector AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N accurately reflects the dual reality of this issue: it is remotely reachable without authentication, but AC:H signals a meaningfully high bar for practical exploitation. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker targets a GnuTLS-protected service using a CBC-mode TLS cipher suite, sending thousands of crafted ciphertext messages to trigger repeated decryption operations and recording the precise response time for each. By statistically correlating timing variations across this large sample set, the attacker reconstructs padding byte values, which in a worst-case padding oracle scenario could be used to make inferences about encrypted data structure. … |
| Remediation | Apply the updated GnuTLS package released by Red Hat via errata RHSA-2026:20613, available at https://access.redhat.com/errata/RHSA-2026:20613. … Detailed patch versions, workarounds, and compensating controls in full report. |
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