Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in potatosalad jose (erlang-jose) allows a remote attacker to exhaust a node's memory with a small crafted JWE token.
\nThe jose_jwe_zip:uncompress/2 function in src/jwe/jose_jwe_zip.erl decompresses the DEFLATE-compressed plaintext of a JWE that carries the optional zip: DEF header by calling zlib:inflate/2 on the entire attacker-controlled stream, with no bound on the output size or the inflation ratio. Raw DEFLATE reaches ratios around 1000:1 on highly repetitive input, so a few-kilobyte token inflates to hundreds of megabytes or gigabytes in a single call.
Decompression runs automatically during decryption through jose_jwe:block_decrypt/2 (JOSE.JWE.block_decrypt/2 in Elixir), before the recipient can inspect or reject the payload. With the common asymmetric key-management algorithms (RSA-OAEP, ECDH-ES) an attacker needs only the recipient's public key to craft such a token, so no authentication or secret material is required. A single small token can exhaust the node's memory and crash the BEAM, denying service to all users.
This issue affects jose: from 1.0.0 before 1.11.13.
"},{"base64":false,"type":"text/markdown","value":"Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in potatosalad jose (erlang-jose) allows a remote attacker to exhaust a node's memory with a small crafted JWE token.\n\nThe `jose_jwe_zip:uncompress/2` function in `src/jwe/jose_jwe_zip.erl` decompresses the DEFLATE-compressed plaintext of a JWE that carries the optional `zip: DEF` header by calling `zlib:inflate/2` on the entire attacker-controlled stream, with no bound on the output size or the inflation ratio. Raw DEFLATE reaches ratios around 1000:1 on highly repetitive input, so a few-kilobyte token inflates to hundreds of megabytes or gigabytes in a single call.\n\nDecompression runs automatically during decryption through `jose_jwe:block_decrypt/2` (`JOSE.JWE.block_decrypt/2` in Elixir), before the recipient can inspect or reject the payload. With the common asymmetric key-management algorithms (RSA-OAEP, ECDH-ES) an attacker needs only the recipient's public key to craft such a token, so no authentication or secret material is required. A single small token can exhaust the node's memory and crash the BEAM, denying service to all users.\n\nThis issue affects jose: from 1.0.0 before 1.11.13."}],"value":"Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in potatosalad jose (erlang-jose) allows a remote attacker to exhaust a node's memory with a small crafted JWE token.\n\nThe jose_jwe_zip:uncompress/2 function in src/jwe/jose_jwe_zip.erl decompresses the DEFLATE-compressed plaintext of a JWE that carries the optional zip: DEF header by calling zlib:inflate/2 on the entire attacker-controlled stream, with no bound on the output size or the inflation ratio. Raw DEFLATE reaches ratios around 1000:1 on highly repetitive input, so a few-kilobyte token inflates to hundreds of megabytes or gigabytes in a single call.\n\nDecompression runs automatically during decryption through jose_jwe:block_decrypt/2 (JOSE.JWE.block_decrypt/2 in Elixir), before the recipient can inspect or reject the payload. With the common asymmetric key-management algorithms (RSA-OAEP, ECDH-ES) an attacker needs only the recipient's public key to craft such a token, so no authentication or secret material is required. A single small token can exhaust the node's memory and crash the BEAM, denying service to all users.\n\nThis issue affects jose: from 1.0.0 before 1.11.13."}],"impacts":[{"capecId":"CAPEC-130","descriptions":[{"lang":"en","value":"CAPEC-130 Excessive Allocation"}]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"LOCAL","baseScore":6.9,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-409","description":"CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-26T19:53:16.336Z","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","shortName":"EEF"},"references":[{"tags":["vendor-advisory","related"],"url":"https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-wfpv-qxp8-x5gm"},{"name":"EEF CNA record for CVE-2026-65627","tags":["related"],"url":"https://cna.erlef.org/cves/CVE-2026-65627.html"},{"name":"OSV record EEF-CVE-2026-65627","tags":["related"],"url":"https://osv.dev/vulnerability/EEF-CVE-2026-65627"},{"name":"Introducing commit a7746ec in potatosalad/erlang-jose","tags":["related"],"url":"https://github.com/potatosalad/erlang-jose/commit/a7746ecd4950f85a393136e449a91dac62b5c429"},{"name":"Fix commit 857eb8e in potatosalad/erlang-jose","tags":["patch"],"url":"https://github.com/potatosalad/erlang-jose/commit/857eb8e7f2d33e2c9ca2189e77226561cacaf2ad"}],"source":{"discovery":"EXTERNAL"},"title":"Decompression bomb via unbounded zlib:inflate in jose_jwe_zip:uncompress/2","workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"Reject JWE tokens that carry a zip header before passing them to jose_jwe:block_decrypt/2. DEFLATE compression is rarely used in legitimate JWE traffic, so untrusted tokens whose protected header contains zip: DEF can be inspected and filtered out before decryption.