From 5f09f797ab4538aa2313312e11543623c87fd759 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Thu, 16 Jul 2026 14:00:06 +0200
Subject: [PATCH] Fix decryption of AES-256 revision 5 PDFs with non-ASCII
 passwords

It fixes #21579.
---
 src/core/crypto.js       |   2 +-
 test/pdfs/.gitignore     |   1 +
 test/pdfs/issue21579.pdf | Bin 0 -> 1394 bytes
 test/test_manifest.json  |   8 +++++++
 test/unit/crypto_spec.js |  47 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 test/pdfs/issue21579.pdf

diff --git a/src/core/crypto.js b/src/core/crypto.js
index 744254e29..567c2f11b 100644
--- a/src/core/crypto.js
+++ b/src/core/crypto.js
@@ -1130,7 +1130,7 @@ class CipherTransformFactory {
     const fileIdBytes = stringToBytes(fileId);
     let passwordBytes;
     if (password) {
-      if (revision === 6) {
+      if (algorithm === 5) {
         try {
           password = utf8StringToString(password);
         } catch {
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index 7cd2904ed..b2c905c79 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -943,3 +943,4 @@
 !issue17333.pdf
 !issue20504.pdf
 !issue20504_skia.pdf
+!issue21579.pdf
diff --git a/test/pdfs/issue21579.pdf b/test/pdfs/issue21579.pdf
new file mode 100644
index 0000000000000000000000000000000000000000..fb01774c0014b07fb329a3cae999b3a260d1937f
GIT binary patch
literal 1394
zcmah}O=}%h7#2hqcOh!rs9+Cbtf1+fk2!PB!P~(3Y^uhjxi%KlE+)Ct<VtdHm^(ML
zu@n@cf^^aDx)3UKRp_D%7wSUHLWzi$DlRGoHPwYbK*2)rJvSe{HVcPg=A37q^Sqz)
z4o|u;LJo-9@NXO6|4<_cqt5KxwR#;TZ=7B(P-62cU+m1IWHO&Gx`+Z{3XP7|igq&+
z<Nm(~ws^^_t!5X^ut+}vDxF@tLS*1z{Id68G*cEp-LjL67tK~~I;YSK27a1hL@@@v
zsiNEIm2==w^fYwfM1MgLj~2mByuoa{0<|tmx6vK9<9^5bYejp$T0jKEA+By!7Wq=`
z>z~i=KR3+JzjSzQW9;>ZkH7il27dHF{{BJz>{oaHx%$_O<xfM`Z;XBL!b5+of3x)7
zch6ste_#IS$Qj?w=YK8q9k;&n*`;sy&tA!ACg0f{dGg|&58wUx>1Q54a_GnFpPbDf
zTYW_QzJ6`(!qCw(H=kQL_f+@b+5>kFsm<FjZ`SEA$)`i-%O{Sn-r9Hji>&_O^o^^3
z&L@|zG?%Yk{QQ!C<*j|kVj$bDZdW1(z7x_`>H29&8ok-7U&#m(l$g9*Y<(Fk7FUX@
zHJ1;RB^yu)t;MP+QPQaLb~7)VD4B-zCR6dToixfb$a3f>zfm=}S2m2JMEk}x+a)pz
zNUvJ(E3vwX>&#6o7ww%oHL9f$?L+~1mG?Fis7{EM!YWB+2$GvrGQxDQ8BGnwTn6eK
zcU~J2U`>r6iaTKic06@fVd^twGAx`?L@Licvo=scL6T}Gq=P;=3RW~{+-ORp9<f0M
zCTtKq#lbL59S)K@<#no@p@DdyI8H#3Q^%aOEVYuP+EHt%0uM2!PAKOYaY1GpgOv%7
z>XLG41P(5eiOWbZhSDr3=9vlvjGK^Qa8)y$rV1!Qb7zPbfH@<gvmoPrN|^H0Q;0-b
z(9Dz;%o?h}#elU0*Hr-TEO&$|E;x}Cr;KXKfDAH|MY#mO4;&#uOJ}`z-g-@_^bjj?
zlBI?T6`5#+V40%Cx97^!%hh;M<xLn1s49EKK<}I?i<32sL=Ep=DC3Y;bQ0}i1o|{y
zsC^I1;CH+aBNRr_eHcx}9xUZ@560;LR+V{cu_*f!t<hR7kbn;EbmB0IgJLHp6dND5
xhaH-!d*ccAP{-g?rwB<?%PdjMq*MZyjs8F5#MUgy%c`FhLNKlk5BrHw`xjoBg;4+i

literal 0
HcmV?d00001

diff --git a/test/test_manifest.json b/test/test_manifest.json
index 02eb0efd2..c8930dcf2 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -14463,5 +14463,13 @@
     "rounds": 1,
     "lastPage": 1,
     "type": "eq"
+  },
+  {
+    "id": "issue21579",
+    "file": "pdfs/issue21579.pdf",
+    "md5": "3e067e3d08edfcb84b70b50937cf247f",
+    "rounds": 1,
+    "type": "eq",
+    "password": "pässwört"
   }
 ]
diff --git a/test/unit/crypto_spec.js b/test/unit/crypto_spec.js
index 1b3751280..7179a8aa5 100644
--- a/test/unit/crypto_spec.js
+++ b/test/unit/crypto_spec.js
@@ -616,6 +616,7 @@ describe("CipherTransformFactory", function () {
 
   let fileId1, fileId2, dict1, dict2, dict3;
   let aes256Dict, aes256IsoDict, aes256BlankDict, aes256IsoBlankDict;
+  let aes256UnicodeDict;
 
   beforeAll(function () {
     fileId1 = unescape("%F6%C6%AF%17%F3rR%8DRM%9A%80%D1%EF%DF%18");
@@ -753,11 +754,38 @@ describe("CipherTransformFactory", function () {
       P: -1084,
       R: 6,
     });
+    aes256UnicodeDict = buildDict({
+      Filter: Name.get("Standard"),
+      V: 5,
+      Length: 256,
+      O: unescape(
+        "%07%E7%C3%30%6B%EE%F5%54%BD%69%11%AC%82%48%76%0C%9D%F0%5A%5C" +
+          "%9E%63%29%9A%24%A0%C2%A1%5B%22%90%30%33%33%33%33%33%33%33%33" +
+          "%44%44%44%44%44%44%44%44"
+      ),
+      U: unescape(
+        "%B0%B5%E1%DA%16%13%4D%FE%F0%0C%4D%09%F2%EE%F2%6A%38%67%49%85" +
+          "%81%10%8D%A0%4F%3E%5D%24%B9%B5%F3%78%11%11%11%11%11%11%11%11" +
+          "%22%22%22%22%22%22%22%22"
+      ),
+      OE: unescape(
+        "%7A%2C%97%53%F5%6C%7C%7C%CA%2F%83%3E%2D%32%33%90%57%DB%21%B9" +
+          "%ED%D2%4B%6F%7D%D9%71%9B%4B%9B%65%42"
+      ),
+      UE: unescape(
+        "%8C%EE%2C%8A%D2%16%82%DC%BB%DF%65%52%72%96%07%C4%AB%6C%99%54" +
+          "%A7%42%BE%BA%43%9F%66%47%F2%68%66%B8"
+      ),
+      Perms: unescape("%E9%4D%1D%8D%96%BE%D3%A9%8D%BD%A6%BE%3E%1A%2A%AD"),
+      P: -1084,
+      R: 5,
+    });
   });
 
   afterAll(function () {
     fileId1 = fileId2 = dict1 = dict2 = dict3 = null;
     aes256Dict = aes256IsoDict = aes256BlankDict = aes256IsoBlankDict = null;
+    aes256UnicodeDict = null;
   });
 
   describe("#ctor", function () {
@@ -779,6 +807,25 @@ describe("CipherTransformFactory", function () {
       });
     });
 
+    describe("AES256 Revision 5 with a non-ASCII password", function () {
+      it("should accept UTF-8 user password", function () {
+        ensurePasswordCorrect(aes256UnicodeDict, fileId1, "pässwört");
+      });
+      it("should accept UTF-8 owner password", function () {
+        ensurePasswordCorrect(aes256UnicodeDict, fileId1, "Öwner");
+      });
+      it("should not accept the UTF-8 bytes as a Latin-1 password", function () {
+        ensurePasswordIncorrect(
+          aes256UnicodeDict,
+          fileId1,
+          unescape("p%C3%A4ssw%C3%B6rt")
+        );
+      });
+      it("should not accept wrong password", function () {
+        ensurePasswordIncorrect(aes256UnicodeDict, fileId1, "wrong");
+      });
+    });
+
     describe("AES256 Revision 6", function () {
       it("should accept user password", function () {
         ensurePasswordCorrect(aes256IsoDict, fileId1, "user");