{"items":[{"id":"NVI-00011765","kind":"vulnerability","title":"fast-jwt: Incomplete patch of CVE-2026-34950: Non-whitespace key-prefix re-enables RSA→HS256 algorithm confusion","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-ww5h-9m49-7xx4","CVE-2026-107722"],"plain_summary":"GitHub lists this reviewed advisory for fast-jwt. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-1e84282598b2916207dcb1d1625cd944"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-08T22:02:08.000Z","value":"9.8 critical","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-1e84282598b2916207dcb1d1625cd944"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-1e84282598b2916207dcb1d1625cd944","url":"https://github.com/advisories/GHSA-ww5h-9m49-7xx4","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-ww5h-9m49-7xx4","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T00:58:23.763Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-1e84282598b2916207dcb1d1625cd944"],"technology":"fast-jwt","known_exclusions":[],"conditions_summary":"### Summary\n\nThe fix for CVE-2026-34950 (CVSS 9.1, released in v6.2.0) is **incomplete**. It adds `key.trim()` to the PEM-detection path in `src/crypto.js`, but `String.prototype.trim()` only strips characters classified as whitespace by the ECMAScript specification. The subsequent `^`-anchored regex (`/^-----BEGIN(?: (RSA))? PUBLIC KEY-----/`) still requires the PEM header at position 0 — so **any non-whitespace leading byte** (control chars, zero-width unicode, `#` comments, HTTP-style headers, PGP wrappers) bypasses detection and falls through to the HMAC verification path, using the RSA public key as the HMAC shared secret. Net result: the **exact same RSA→HS256 algorithm-confusion attack** the original CVE addressed is fully re-enabled with a slightly different leading byte.\n\n**Attack prerequisites are identical to CVE-2026-34950**: attacker knows the target's public RSA key (which is public by definition), and the target loads that key from a source whose content may have a non-whitespace prefix (DB column with corrupted encoding, YAML config with inline comment, copy-paste from formatted document, etc.).\n\n**Verified on fast-jwt@6.2.2 (latest as of 2026-04-23) with a 10-line ","public_affected_ranges":[">= 6.2.0, <= 6.2.4"]}],"null_published_at":"2026-11-01T01:03:56.601Z","source_updated_at":"2026-10-08T22:02:08.000Z","source_disclosed_at":"2026-10-08T22:02:07.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-01T00:58:23.763Z"}],"next_cursor":null,"snapshot_revision":"42594"}