CVE-2026-65627
Received Received - Intake

Memory Exhaustion in jose_jwe_zip via Highly Compressed JWE Tokens

Publication date: 2026-10-26

Last updated on: 2026-10-26

Assigner: EEF

Description
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. The 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.

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Meta Information

Published
2026-10-26
Last Modified
2026-10-26
Generated
2026-10-26
AI Q&A
2026-10-26
EPSS Evaluated
N/A
NVD
CVE-2026-65627
EUVD
EUVD-2026-110306

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
potatosalad jose 1.0.0
potatosalad jose a7746ecd4950f85a393136e449a91dac62b5c429

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-409 The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.

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Executive Summary

This vulnerability involves improper handling of highly compressed data in the jose library (erlang-jose). A remote attacker can exploit it by sending a small crafted JWE token with a DEFLATE compression header. During decryption, the system decompresses the token without size limits, causing massive memory allocation (up to 1000x the original size). This can crash the BEAM runtime, denying service to all users.

Detection Guidance

Detect this vulnerability by monitoring for unusually large memory allocations during JWE token decryption processes. Check logs for crashes in BEAM runtime or OOM-killer events. Inspect network traffic for JWE tokens with zip: DEF headers, as these indicate potential exploitation attempts.

Impact Analysis

An attacker can crash your system by sending a small JWE token that inflates to hundreds of megabytes or gigabytes during decryption. This causes memory exhaustion, leading to service disruption or denial of service for all users. No authentication or secret material is required, only the recipient's public key.

Mitigation Strategies
  • Upgrade the jose library to version 1.11.13 or later to apply the official fix.
  • Reject JWE tokens containing the zip: DEF header before decryption to prevent decompression bomb attacks.
  • Set a maximum decompressed size limit (e.g., 1 MiB) using jose:zip_size_maximum/0 or the zip_size_maximum application environment key.
  • Monitor memory usage and BEAM runtime stability for signs of resource exhaustion.

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