{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-14535", "assignerOrgId": "aa17e1a1-c329-4d6e-a1ed-8d0188aea082", "state": "PUBLISHED", "assignerShortName": "BombadilSystems", "dateReserved": "2026-07-03T00:02:55.918Z", "datePublished": "2026-07-04T13:31:14.937Z", "dateUpdated": "2026-07-06T14:58:34.718Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "aa17e1a1-c329-4d6e-a1ed-8d0188aea082", "shortName": "BombadilSystems", "dateUpdated": "2026-07-04T13:31:14.937Z" }, "title": "Fickling MLAllowlist analysis pass rendered inoperative by shared mutable state in AnalysisContext.shorten_code()", "datePublic": "2026-06-28T00:08:00.000Z", "problemTypes": [ { "descriptions": [ { "lang": "en", "cweId": "CWE-693", "description": "CWE-693 Protection Mechanism Failure", "type": "CWE" } ] } ], "impacts": [ { "descriptions": [ { "lang": "en", "value": "An attacker can craft a malicious pickle file that imports any standard library module not in fickling's UNSAFE_IMPORTS denylist. Because the MLAllowlist check is silently skipped due to shared state pollution from UnsafeImportsML, fickling's check_safety() returns LIKELY_SAFE. When used with fickling.load(), the payload is deserialized and arbitrary code executes in the victim's environment. This is distinct from denylist incompleteness (CWE-184) because the allowlist mechanism was specifically designed to catch imports that the denylist misses, and a code defect renders it entirely inoperative." } ] } ], "affected": [ { "vendor": "trailofbits", "product": "fickling", "collectionURL": "https://pypi.org/project/fickling/", "packageName": "fickling", "versions": [ { "status": "affected", "version": "0", "lessThanOrEqual": "0.1.11", "versionType": "custom" }, { "status": "unaffected", "version": "0.1.12", "versionType": "custom" } ], "defaultStatus": "unaffected" } ], "descriptions": [ { "lang": "en", "value": "In Trail of Bits fickling versions up to and including 0.1.11, the UnsafeImportsML analysis pass unconditionally calls AnalysisContext.shorten_code(node) on every import node it inspects, regardless of whether the import is flagged as unsafe. This call registers the shortened code representation in the shared AnalysisContext.reported_shortened_code set. When the MLAllowlist analysis pass subsequently runs, it calls the same shorten_code() method, receives already_reported=True for every import, and executes a continue statement that skips its allowlist check entirely. This renders MLAllowlist dead code for all imports — it never evaluates whether an import is in the ML allowlist or not. The MLAllowlist pass was designed to catch imports of modules outside the known-safe ML ecosystem (torch, numpy, transformers, etc.) that slip past the UnsafeImports denylist. With MLAllowlist inoperative, any standard library module not in the UNSAFE_IMPORTS denylist can be invoked via pickle deserialization while fickling's check_safety() returns LIKELY_SAFE. The fickling.load() API chains check_safety() into pickle.loads() as an explicit security gate, meaning a LIKELY_SAFE verdict causes the payload to be deserialized and executed. The root cause is shared mutable state between independently-correct analysis passes — UnsafeImportsML works as designed in isolation, MLAllowlist works as designed in isolation, but the shared reported_shortened_code set causes UnsafeImportsML to poison MLAllowlist's deduplication logic.", "supportingMedia": [ { "type": "text/html", "base64": false, "value": "
In Trail of Bits fickling versions up to and including 0.1.11, the UnsafeImportsML analysis pass unconditionally calls AnalysisContext.shorten_code(node) on every import node it inspects, regardless of whether the import is flagged as unsafe. This call registers the shortened code representation in the shared AnalysisContext.reported_shortened_code set. When the MLAllowlist analysis pass subsequently runs, it calls the same shorten_code() method, receives already_reported=True for every import, and executes a continue statement that skips its allowlist check entirely. This renders MLAllowlist dead code for all imports — it never evaluates whether an import is in the ML allowlist or not. The MLAllowlist pass was designed to catch imports of modules outside the known-safe ML ecosystem (torch, numpy, transformers, etc.) that slip past the UnsafeImports denylist. With MLAllowlist inoperative, any standard library module not in the UNSAFE_IMPORTS denylist can be invoked via pickle deserialization while fickling's check_safety() returns LIKELY_SAFE. The fickling.load() API chains check_safety() into pickle.loads() as an explicit security gate, meaning a LIKELY_SAFE verdict causes the payload to be deserialized and executed. The root cause is shared mutable state between independently-correct analysis passes — UnsafeImportsML works as designed in isolation, MLAllowlist works as designed in isolation, but the shared reported_shortened_code set causes UnsafeImportsML to poison MLAllowlist's deduplication logic.
" } ] } ], "references": [ { "url": "https://github.com/trailofbits/fickling/security/advisories/GHSA-cffv-grgg-g429", "name": "GitHub Security Advisory GHSA-cffv-grgg-g429" }, { "url": "https://github.com/trailofbits/fickling/pull/278", "name": "Fix PR #278 — Split shorten_code() formatting from dedup tracking, make MLAllowlist opt-in" }, { "url": "https://github.com/trailofbits/fickling/commit/41ce7cb01edd97072994039574a2301ebb3f463d", "name": "Fix commit 41ce7cb (squash merge of PR #278)" }, { "url": "https://github.com/trailofbits/fickling/releases/tag/v0.1.12", "name": "Fickling v0.1.12 release" } ], "metrics": [ { "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ], "cvssV3_1": { "version": "3.1", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH", "baseSeverity": "HIGH", "baseScore": 8.8, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H" } } ], "credits": [ { "lang": "en", "value": "Christopher Aziz (Bombadil Systems LLC)", "type": "finder" } ], "source": { "discovery": "EXTERNAL" }, "x_generator": { "engine": "Vulnogram 1.0.2" } }, "adp": [ { "references": [ { "url": "https://github.com/trailofbits/fickling/security/advisories/GHSA-cffv-grgg-g429", "tags": [ "exploit" ] } ], "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-07-06T14:58:30.612222Z", "id": "CVE-2026-14535", "options": [ { "Exploitation": "poc" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-06T14:58:34.718Z" } } ] } }