CVE-2026-65626 (GCVE-0-2026-65626)
Vulnerability from cvelistv5
Published
2026-10-26 19:53
Modified
2026-11-02 19:43
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-203 - Observable Discrepancy
Summary
The pure-Erlang RSAES-PKCS1-v1_5 decryption in the jose_jwa_pkcs1 module is a Bleichenbacher padding oracle. eme_pkcs1_decode/2 returns the recovered message when a decrypted block has valid PKCS#1 v1.5 padding (a leading 0x00 0x02, a padding string of at least eight non-zero bytes, and a 0x00 separator) and returns a distinct error result otherwise, and rsaes_pkcs1_decrypt/2 additionally returns {error, {badsize, _}} when the length check fails. The implementation applies no implicit-rejection countermeasure (RFC 8017 §7.2.2): it does not substitute a deterministic pseudo-random plaintext on a padding failure, so a one-bit padding-conformance signal leaks to the caller. Because the underlying modular exponentiation in dp/2 is a raw, non-blinded crypto:mod_pow/3, the padding check also stays distinguishable by timing even when an application normalizes every failure to a single error value.
An unauthenticated attacker who knows only the public RSA key and can submit ciphertexts to a decryption endpoint that unwraps RSA1_5 JWE keys (or otherwise calls decrypt_private/3 with rsa_pkcs1_padding) can use this oracle to recover the plaintext of intercepted ciphertexts, such as content-encryption keys and thus the protected message, or to forge signatures, through roughly 10^4 to 10^6 adaptive chosen-ciphertext queries.
This issue affects jose: from 1.3.0 before 1.11.13.
References
Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| potatosalad | jose |
Version: 1.3.0 ≤ cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:* |
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|
|||||||||
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Because the underlying modular exponentiation in dp/2 is a raw, non-blinded crypto:mod_pow/3, the padding check also stays distinguishable by timing even when an application normalizes every failure to a single error value.\\n\\nAn unauthenticated attacker who knows only the public RSA key and can submit ciphertexts to a decryption endpoint that unwraps RSA1_5 JWE keys (or otherwise calls decrypt_private/3 with rsa_pkcs1_padding) can use this oracle to recover the plaintext of intercepted ciphertexts, such as content-encryption keys and thus the protected message, or to forge signatures, through roughly 10^4 to 10^6 adaptive chosen-ciphertext queries.\\n\\nThis issue affects jose: from 1.3.0 before 1.11.13.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eThe pure-Erlang RSAES-PKCS1-v1_5 decryption in the \u003ccode\u003ejose_jwa_pkcs1\u003c/code\u003e module is a Bleichenbacher padding oracle. \u003ccode\u003eeme_pkcs1_decode/2\u003c/code\u003e returns the recovered message when a decrypted block has valid \u003ccode\u003ePKCS#1\u003c/code\u003e v1.5 padding (a leading \u003ccode\u003e0x00 0x02\u003c/code\u003e, a padding string of at least eight non-zero bytes, and a \u003ccode\u003e0x00\u003c/code\u003e separator) and returns a distinct error result otherwise, and \u003ccode\u003ersaes_pkcs1_decrypt/2\u003c/code\u003e additionally returns \u003ccode\u003e{error, {badsize, _}}\u003c/code\u003e when the length check fails. The implementation applies no implicit-rejection countermeasure (RFC 8017 \\u00a77.2.2): it does not substitute a deterministic pseudo-random plaintext on a padding failure, so a one-bit padding-conformance signal leaks to the caller. Because the underlying modular exponentiation in \u003ccode\u003edp/2\u003c/code\u003e is a raw, non-blinded \u003ccode\u003ecrypto:mod_pow/3\u003c/code\u003e, the padding check also stays distinguishable by timing even when an application normalizes every failure to a single error value.\u003c/p\u003e\\n\u003cp\u003eAn unauthenticated attacker who knows only the public RSA key and can submit ciphertexts to a decryption endpoint that unwraps RSA1_5 JWE keys (or otherwise calls \u003ccode\u003edecrypt_private/3\u003c/code\u003e with \u003ccode\u003ersa_pkcs1_padding\u003c/code\u003e) can use this oracle to recover the plaintext of intercepted ciphertexts, such as content-encryption keys and thus the protected message, or to forge signatures, through roughly 10^4 to 10^6 adaptive chosen-ciphertext queries.\u003c/p\u003e\\n\u003cp\u003eThis issue affects jose: from 1.3.0 before 1.11.13.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"The pure-Erlang RSAES-PKCS1-v1_5 decryption in the `jose_jwa_pkcs1` module is a Bleichenbacher padding oracle. `eme_pkcs1_decode/2` returns the recovered message when a decrypted block has valid `PKCS#1` v1.5 padding (a leading `0x00 0x02`, a padding string of at least eight non-zero bytes, and a `0x00` separator) and returns a distinct error result otherwise, and `rsaes_pkcs1_decrypt/2` additionally returns `{error, {badsize, _}}` when the length check fails. The implementation applies no implicit-rejection countermeasure (RFC 8017 \\u00a77.2.2): it does not substitute a deterministic pseudo-random plaintext on a padding failure, so a one-bit padding-conformance signal leaks to the caller. Because the underlying modular exponentiation in `dp/2` is a raw, non-blinded `crypto:mod_pow/3`, the padding check also stays distinguishable by timing even when an application normalizes every failure to a single error value.\\n\\nAn unauthenticated attacker who knows only the public RSA key and can submit ciphertexts to a decryption endpoint that unwraps RSA1_5 JWE keys (or otherwise calls `decrypt_private/3` with `rsa_pkcs1_padding`) can use this oracle to recover the plaintext of intercepted ciphertexts, such as content-encryption keys and thus the protected message, or to forge signatures, through roughly 10^4 to 10^6 adaptive chosen-ciphertext queries.\\n\\nThis issue affects jose: from 1.3.0 before 1.11.13.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-203\", \"description\": \"CWE-203 Observable Discrepancy\"}]}], \"configurations\": [{\"lang\": \"en\", \"value\": \"The vulnerable code path is only reached when jose performs RSAES-PKCS1-v1_5 decryption with its pure-Erlang fallback (the jose_jwa_pkcs1 module) instead of the native OTP public_key implementation. This requires the crypto_fallback option to be enabled (application:set_env(jose, crypto_fallback, true), or JOSE.crypto_fallback(true) in Elixir) and the OTP runtime not to provide native RSA1_5 decryption. When native OTP RSA support is selected, decryption does not go through jose_jwa_pkcs1.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eThe vulnerable code path is only reached when jose performs RSAES-PKCS1-v1_5 decryption with its pure-Erlang fallback (the \u003ccode\u003ejose_jwa_pkcs1\u003c/code\u003e module) instead of the native OTP \u003ccode\u003epublic_key\u003c/code\u003e implementation. This requires the crypto_fallback option to be enabled (\u003ccode\u003eapplication:set_env(jose, crypto_fallback, true)\u003c/code\u003e, or \u003ccode\u003eJOSE.crypto_fallback(true)\u003c/code\u003e in Elixir) and the OTP runtime not to provide native RSA1_5 decryption. When native OTP RSA support is selected, decryption does not go through \u003ccode\u003ejose_jwa_pkcs1\u003c/code\u003e.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"The vulnerable code path is only reached when jose performs RSAES-PKCS1-v1_5 decryption with its pure-Erlang fallback (the `jose_jwa_pkcs1` module) instead of the native OTP `public_key` implementation. This requires the crypto_fallback option to be enabled (`application:set_env(jose, crypto_fallback, true)`, or `JOSE.crypto_fallback(true)` in Elixir) and the OTP runtime not to provide native RSA1_5 decryption. When native OTP RSA support is selected, decryption does not go through `jose_jwa_pkcs1`.\", \"base64\": false}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"1.11.13\", \"versionStartIncluding\": \"1.3.0\"}], \"operator\": \"OR\"}], \"operator\": \"AND\"}], \"providerMetadata\": {\"orgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"shortName\": \"EEF\", \"dateUpdated\": \"2026-10-26T19:53:05.620Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-65626\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-11-02T19:43:05.115Z\", \"dateReserved\": \"2026-07-22T13:55:59.401Z\", \"assignerOrgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"datePublished\": \"2026-10-26T19:53:05.620Z\", \"assignerShortName\": \"EEF\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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