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Rebase to 1.5.7

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Resolves: RHEL-168728
Signed-off-by: Rafael Guterres Jeffman <rjeffman@redhat.com>
This commit is contained in:
Rafael Guterres Jeffman 2026-06-23 01:00:13 -03:00
parent 9068a807ec
commit 75d31527a0
5 changed files with 49 additions and 158 deletions
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1
.gitignore vendored
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@ -13,3 +13,4 @@
/jwcrypto-1.4.1.tar.gz
/jwcrypto-1.4.2.tar.gz
/jwcrypto-1.5.6.tar.gz
/jwcrypto-1.5.7.tar.gz

153
0002-Limit-max-plaintext-size-for-JWE-decompression.patch
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@ -1,153 +0,0 @@
From 25db861d8b29434838669a94a843af03d29ea6ed Mon Sep 17 00:00:00 2001
From: Simo Sorce <simo@redhat.com>
Date: Mon, 6 Apr 2026 10:37:20 -0400
Subject: [PATCH] Limit max plaintext size for JWE decompression
This change introduces a maximum plaintext size limit (defaulting to 100MB)
during JWE decryption and updates the decompression logic to enforce it safely
using zlib.decompressobj. The decrypt method now accepts a max_plaintext
parameter to allow overriding the default limit.
This mitigates memory exhaustion and decompression bomb attacks when
processing highly compressed malicious JWE payloads.
Fixes CVE-2026-39373
Signed-off-by: Simo Sorce <simo@redhat.com>
---
jwcrypto/jwe.py | 27 +++++++++++++++++++++------
jwcrypto/tests.py | 34 ++++++++++++++++++++++++++--------
2 files changed, 47 insertions(+), 14 deletions(-)
diff --git a/jwcrypto/jwe.py b/jwcrypto/jwe.py
index e01aa1d..7895928 100644
--- a/jwcrypto/jwe.py
+++ b/jwcrypto/jwe.py
@@ -12,7 +12,8 @@
# Limit the amount of data we are willing to decompress by default.
default_max_compressed_size = 256 * 1024
-
+# Limit the maximum plaintext size to 100MB by default.
+default_max_plaintext_size = 100 * 1024 * 1024
# RFC 7516 - 4.1
# name: (description, supported?)
@@ -376,7 +377,7 @@ def _unwrap_decrypt(self, alg, enc, key, enckey, header,
return data
# FIXME: allow to specify which algorithms to accept as valid
- def _decrypt(self, key, ppe):
+ def _decrypt(self, key, ppe, max_plaintext=default_max_plaintext_size):
jh = self._get_jose_header(ppe.get('header', None))
@@ -434,19 +435,29 @@ def _decrypt(self, key, ppe):
raise InvalidJWEData(
'Compressed data exceeds maximum allowed'
'size' + f' ({default_max_compressed_size})')
- self.plaintext = zlib.decompress(data, -zlib.MAX_WBITS)
+ do = zlib.decompressobj(wbits=-zlib.MAX_WBITS)
+ self.plaintext = do.decompress(data, max_plaintext)
+ if do.unconsumed_tail or not do.eof:
+ self.plaintext = None
+ raise InvalidJWEData(
+ 'Compressed data exceeds maximum allowed'
+ 'output size' + f' ({max_plaintext})')
elif compress is None:
self.plaintext = data
else:
raise ValueError('Unknown compression')
- def decrypt(self, key):
+ def decrypt(self, key, max_plaintext=0):
"""Decrypt a JWE token.
:param key: The (:class:`jwcrypto.jwk.JWK`) decryption key.
:param key: A (:class:`jwcrypto.jwk.JWK`) decryption key,
or a (:class:`jwcrypto.jwk.JWKSet`) that contains a key indexed
by the 'kid' header or (deprecated) a string containing a password.
+ :param max_plaintext: Maximum plaintext size allowed, 0 means
+ the library default applies. Application writers are recommended
+ to set a limit here if they know what is the max plaintext size
+ for their application.
:raises InvalidJWEOperation: if the key is not a JWK object.
:raises InvalidJWEData: if the ciphertext can't be decrypted or
@@ -454,6 +465,10 @@ def decrypt(self, key):
:raises JWKeyNotFound: if key is a JWKSet and the key is not found.
"""
+ self.plaintext = None
+ if max_plaintext == 0:
+ max_plaintext = default_max_plaintext_size
+
if 'ciphertext' not in self.objects:
raise InvalidJWEOperation("No available ciphertext")
self.decryptlog = []
@@ -462,14 +477,14 @@ def decrypt(self, key):
if 'recipients' in self.objects:
for rec in self.objects['recipients']:
try:
- self._decrypt(key, rec)
+ self._decrypt(key, rec, max_plaintext=max_plaintext)
except Exception as e: # pylint: disable=broad-except
if isinstance(e, JWKeyNotFound):
missingkey = True
self.decryptlog.append('Failed: [%s]' % repr(e))
else:
try:
- self._decrypt(key, self.objects)
+ self._decrypt(key, self.objects, max_plaintext=max_plaintext)
except Exception as e: # pylint: disable=broad-except
if isinstance(e, JWKeyNotFound):
missingkey = True
diff --git a/jwcrypto/tests.py b/jwcrypto/tests.py
index cc612eb..3fc4b16 100644
--- a/jwcrypto/tests.py
+++ b/jwcrypto/tests.py
@@ -2124,18 +2124,36 @@ def test_jwe_decompression_max(self):
enc = jwe.JWE(payload.encode('utf-8'),
recipient=key,
protected=protected_header).serialize(compact=True)
+ check = jwe.JWE()
+ check.deserialize(enc)
with self.assertRaises(jwe.InvalidJWEData):
- check = jwe.JWE()
- check.deserialize(enc)
check.decrypt(key)
- defmax = jwe.default_max_compressed_size
- jwe.default_max_compressed_size = 1000000000
- # ensure we can eraise the limit and decrypt
- check = jwe.JWE()
- check.deserialize(enc)
+ # raise the limit on compressed token size so we can decrypt
+ defcmax = jwe.default_max_compressed_size
+ jwe.default_max_compressed_size = 10 * 1024 * 1024
+
+ # this passes if we explicitly allow larger plaintext via API
+ check.decrypt(key, max_plaintext=1000000000)
+
+ # this will still fail because the max plaintext length clamps this
+ with self.assertRaises(jwe.InvalidJWEData):
+ check.decrypt(key)
+
+ # ensure that now this can work with changed defaults
+ defpmax = jwe.default_max_plaintext_size
+ jwe.default_max_plaintext_size = 1000000000
check.decrypt(key)
- jwe.default_max_compressed_size = defmax
+
+ # restore limits
+ jwe.default_max_compressed_size = defcmax
+
+ # check that this fails the max compressed header limits
+ with self.assertRaises(jwe.InvalidJWEData):
+ check.decrypt(key)
+
+ # restore plaintext limits
+ jwe.default_max_plaintext_size = defpmax
class JWATests(unittest.TestCase):

40
0002-handle-unsafe-skip-rsa-key-validation-compat.patch Normal file
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@ -0,0 +1,40 @@
--- jwcrypto-1.5.7/jwcrypto/jwk.py 2026-06-03 13:07:15
+++ jwcrypto-1.5.7-new/jwcrypto/jwk.py 2026-06-23 00:49:09
@@ -839,9 +839,14 @@
def _rsa_pri(self):
k = self._cache_pri_k
if k is None:
- u = self.unsafe_skip_rsa_key_validation
- k = self._rsa_pri_n().private_key(default_backend(),
- unsafe_skip_rsa_key_validation=u)
+ try:
+ u = self.unsafe_skip_rsa_key_validation
+ k = self._rsa_pri_n().private_key(
+ default_backend(),
+ unsafe_skip_rsa_key_validation=u)
+ except TypeError:
+ k = self._rsa_pri_n().private_key(
+ default_backend())
self._cache_pri_k = k
return k
@@ -997,10 +1002,15 @@
"""
try:
- u = self.unsafe_skip_rsa_key_validation
- key = serialization.load_pem_private_key(
- data, password=password, backend=default_backend(),
- unsafe_skip_rsa_key_validation=u)
+ try:
+ u = self.unsafe_skip_rsa_key_validation
+ key = serialization.load_pem_private_key(
+ data, password=password, backend=default_backend(),
+ unsafe_skip_rsa_key_validation=u)
+ except TypeError:
+ key = serialization.load_pem_private_key(
+ data, password=password,
+ backend=default_backend())
except ValueError as e:
if password is not None:
raise e

11
python-jwcrypto.spec
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@ -18,8 +18,8 @@
%global srcname jwcrypto
Name: python-%{srcname}
Version: 1.5.6
Release: 3%{?dist}
Version: 1.5.7
Release: 1%{?dist}
Summary: Implements JWK, JWS, JWE specifications using python-cryptography
License: LGPLv3+
@ -27,8 +27,7 @@ URL: https://github.com/latchset/%{srcname}
Source0: https://github.com/latchset/%{srcname}/releases/download/v%{version}/%{srcname}-%{version}.tar.gz
Patch1: 0001-ignore-deprecated-annotation.patch
# Security fix for CVE-2026-39373
Patch2: 0002-Limit-max-plaintext-size-for-JWE-decompression.patch
Patch2: 0002-handle-unsafe-skip-rsa-key-validation-compat.patch
BuildArch: noarch
%if 0%{?with_python2}
@ -131,6 +130,10 @@ rm -rf %{buildroot}%{python3_sitelib}/%{srcname}/__pycache__/tests{,-cookbook}.*
%changelog
* Tue Jun 23 2026 Rafael Jeffman <rjeffman@redhat.com> - 1.5.7-1
- Rebase to 1.5.7
Resolves: RHEL-168728
* Tue Apr 14 2026 Rafael Jeffman <rjeffman@redhat.com> - 1.5.6-3
- Limit max plaintext size for JWE decompression
Resolves: RHEL-166029

2
sources
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@ -1 +1 @@
SHA512 (jwcrypto-1.5.6.tar.gz) = 1db62cf247bc006f1737c4603b80e5ca87e1a3db3b3dc37183a9725a8b3cae4baba706b2ec596119877130ab4d56525a01fb9d7efca07e59811d78021aa7ebf5
SHA512 (jwcrypto-1.5.7.tar.gz) = 9f05edc9c0969c3415fede22cc20bd0036187f7acd0477f82f7288809ccd9af9d00ec9f4bff7c6b47083c158395a3fc11024156ef5f2dc148820288002098ef9