{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/products/libgnutls/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":8.2,"id":"CVE-2026-5260"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["libgnutls"],"_cs_severities":["high"],"_cs_tags":["heap-overread","information-disclosure","tls","cve"],"_cs_type":"advisory","_cs_vendors":["gnu"],"content_html":"\u003cp\u003eCVE-2026-5260 describes a heap overread vulnerability found in libgnutls. The vulnerability arises during RSA key exchange when a server uses an RSA key backed by a PKCS#11 token. An attacker can exploit this flaw by sending an extremely short premaster secret. This leads to a short heap overread, a type of memory corruption vulnerability. Successful exploitation could result in the disclosure of sensitive information. This vulnerability impacts systems using vulnerable versions of libgnutls and could potentially affect any application or service relying on the library for secure communication.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker initiates an RSA key exchange with a server using a libgnutls implementation.\u003c/li\u003e\n\u003cli\u003eThe server\u0026rsquo;s RSA key is backed by a PKCS#11 token for cryptographic operations.\u003c/li\u003e\n\u003cli\u003eAttacker sends a crafted TLS ClientHello message to initiate the handshake.\u003c/li\u003e\n\u003cli\u003eThe attacker provides an extremely short premaster secret in the ClientKeyExchange message.\u003c/li\u003e\n\u003cli\u003elibgnutls processes the short premaster secret during the RSA decryption process.\u003c/li\u003e\n\u003cli\u003eDue to insufficient bounds checking, the processing of the short premaster secret triggers a heap overread.\u003c/li\u003e\n\u003cli\u003eThe heap overread allows the attacker to potentially read beyond the allocated memory buffer.\u003c/li\u003e\n\u003cli\u003eSensitive information is disclosed, potentially compromising the confidentiality of the communication.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-5260 can lead to information disclosure. Specifically, an attacker could potentially read sensitive data stored in memory adjacent to the overread buffer. The impact is limited to information disclosure, but the sensitivity of the disclosed data depends on the context and the application using libgnutls. The number of potential victims is broad, as many applications rely on libgnutls for TLS/SSL functionality.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eUpgrade to the latest version of libgnutls that contains the fix for CVE-2026-5260.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rules provided in this brief to your SIEM to detect potential exploitation attempts.\u003c/li\u003e\n\u003cli\u003eMonitor network traffic for anomalous TLS handshake patterns involving short premaster secrets using network connection logs.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-26T22:19:06Z","date_published":"2026-05-26T22:19:06Z","id":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-5260-gnutls-heap-overread/","summary":"A remote attacker can trigger a heap overread in libgnutls by sending an extremely short premaster secret during an RSA key exchange to a server using an RSA key backed by a PKCS#11 token, potentially leading to information disclosure.","title":"CVE-2026-5260: libgnutls Heap Overread via Short Premaster Secret","url":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-5260-gnutls-heap-overread/"}],"language":"en","title":"CraftedSignal Threat Feed — Libgnutls","version":"https://jsonfeed.org/version/1.1"}