Likely fixed by https://github.com/twisted/twisted/pull/12661 (theoretically
more changes may be needed, I didn't check if the upstream CI runs with this
pyopenssl).

pyopenssl 26.3.0 is available in experimental.

[ERROR]
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/foolscap/appserver/cli.py", line 124, in
run
    a = AppServer(basedir, stdout)
  File "/usr/lib/python3/dist-packages/foolscap/appserver/server.py", line 74,
in __init__
    self.tub = Tub(certFile=os.path.join(basedir, "tub.pem"))
  File "/usr/lib/python3/dist-packages/foolscap/pb.py", line 192, in __init__
    self.setupEncryptionFile(certFile)
  File "/usr/lib/python3/dist-packages/foolscap/pb.py", line 204, in
setupEncryptionFile
    self.setupEncryption(certData)
  File "/usr/lib/python3/dist-packages/foolscap/pb.py", line 215, in
setupEncryption
    cert = self.createCertificate()
  File "/usr/lib/python3/dist-packages/foolscap/pb.py", line 419, in
createCertificate
    return crypto.createCertificate()
  File "/usr/lib/python3/dist-packages/foolscap/crypto.py", line 77, in
createCertificate
    req = keypair.certificateRequest(dn, digestAlgorithm="sha256")
  File "/usr/lib/python3/dist-packages/twisted/internet/_sslverify.py", line
731, in certificateRequest
    return self.requestObject(distinguishedName, digestAlgorithm).dump(format)
  File "/usr/lib/python3/dist-packages/twisted/internet/_sslverify.py", line
717, in requestObject
    req = crypto.X509Req()
  File "/usr/lib/python3/dist-packages/cryptography/utils.py", line 76, in
__getattr__
    obj = getattr(self._module, name)
builtins.AttributeError: module 'OpenSSL.crypto' has no attribute 'X509Req'

Hello,

Bug #1140931 in twisted reported by you has been fixed in the
Git repository and is awaiting an upload. You can see the commit
message below and you can check the diff of the fix at:

https://salsa.debian.org/python-team/packages/twisted/-/commit/31083f4b69d740a9d029f701a9d8bb53d493d6f8
------------------------------------------------------------------------
Replace OpenSSL.crypto.X509Req with pyca/cryptography CSR

Closes: #1140931
------------------------------------------------------------------------

(this message was generated automatically)
-- 
Greetings

https://bugs.debian.org/1140931

We believe that the bug you reported is fixed in the latest version of
twisted, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1140931@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Colin Watson <cjwatson@debian.org> (supplier of updated twisted package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Mon, 29 Jun 2026 11:22:56 +0100
Source: twisted
Architecture: source
Version: 26.4.0-3
Distribution: unstable
Urgency: medium
Maintainer: Debian Python Team <team+python@tracker.debian.org>
Changed-By: Colin Watson <cjwatson@debian.org>
Closes: 1140931
Changes:
 twisted (26.4.0-3) unstable; urgency=medium
 .
   * Replace OpenSSL.crypto.X509Req with pyca/cryptography CSR (closes:
     #1140931).
   * Drop "Priority: optional", default as of dpkg-dev 1.22.13.
   * Standards-Version: 4.7.4.
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Files:
 f25a275b6fb65bb4c6df07e5ed101d49 3020 python optional twisted_26.4.0-3.dsc
 c3695739ff7d63509928da89ba86a0ce 30768 python optional twisted_26.4.0-3.debian.tar.xz
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Git-Tag-Info: tag=b3d100c72669ffd6f825207079083700fff00b00 fp=ac0a4ff12611b6fccf01c111393587d97d86500b
Git-Tag-Tagger: Colin Watson <cjwatson@debian.org>
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