Since at least gpg4win-5.0.2 piping into gpgsm for verification of detached signatures fails, e.g. tested on gpg4win-5.1.0-beta658 @ win11:
c:\Users\g10>type smime.signed-only.txt | gpgsm -v --debug-all --status-fd=2 --verify smime.signed-only.txt.p7s - gpgsm: reading options from '[cmdline]' gpgsm: reading options from 'C:/Users/g10/AppData/Roaming/gnupg/common.conf' gpgsm: enabled debug flags: x509 mpi crypto memory cache memstat hashing ipc clock lookup gpgsm: enabled compatibility flags: gpgsm: can't open '-': No such file or directory [GNUPG:] FAILURE gpgsm-exit 50331649 gpgsm: cert_chain_cache: cached=0 gpgsm: random usage: poolsize=600 mixed=0 polls=0/0 added=0/0 outmix=0 getlvl1=0/0 getlvl2=0/0 gpgsm: rndjent stat: collector=0x0000000000000000 calls=0 bytes=0 gpgsm: secmem usage: 0/16384 bytes in 0 blocks
This used to work in e.g. vsd-3.3.7 / gpgsm 2.2.54, and also in the gpgsm 2.4.9 provided by git for windows:
c:\Users\g10>type smime.signed-only.txt | gpgsm -v --status-fd=2 --verify smime.signed-only.txt.p7s - gpgsm: enabled compatibility flags: de-vs-trustlist gpgsm: detached signature [GNUPG:] NEWSIG gpgsm: Signature made 2026-07-06 13:16:47 UTC gpgsm: using rsa3072 key 7C6A4442C88AA009D1B82BD267F99891C2311DD2 gpgsm: algorithm: RSA + SHA256 gpgsm: certificate is good gpgsm: validation model used: shell [GNUPG:] VERIFICATION_COMPLIANCE_MODE 23 [GNUPG:] GOODSIG 7C6A4442C88AA009D1B82BD267F99891C2311DD2 /CN=Test Tester/OU=demo/O=g10 Code GmbH/C=DE [GNUPG:] VALIDSIG 7C6A4442C88AA009D1B82BD267F99891C2311DD2 2026-07-06 20260706T131647 20630405T170000 0 0 1 8 00 gpgsm: Good signature from "/CN=Test Tester/OU=demo/O=g10 Code GmbH/C=DE" gpgsm: aka "ted.tester@demo.gnupg.com" [GNUPG:] TRUST_FULLY 0 shell
Piping of embedded signatures (without -) still works on gpg4win-5.1.0-beta658 @ win11:
C:\Users\g10>echo test | gpgsm --sign --local-user Ted | gpgsm --verify [...] gpgsm: Good signature from "/CN=Test Tester/OU=demo/O=g10 Code GmbH/C=DE" gpgsm: aka "ted.tester@demo.gnupg.com"