CVE-2025-50420

Il vendor (freedesktop, manutentore di Poppler) ha riconosciuto il problema e risolto il bug. La correzione è stata committata nel loro repository ufficiale.

Ecco il link pubblico alla patch / al commit fornito dal vendor:

https://gitlab.freedesktop.org/poppler/poppler/-/issues/1613<br>
https://gitlab.freedesktop.org/poppler/poppler/-/merge_requests/1849<br>
https://gitlab.freedesktop.org/poppler/poppler/-/commit/08d7894e4dd0e313c179e30f06ad8f546619b1b3

Ciò conferma che la vulnerabilità è stata riconosciuta e risolta.



Le versioni di Poppler precedenti alla 25.07.0 presentano una vulnerabilità nella logica di elaborazione PDFDoc dello strumento pdfseparate: un dizionario "/Annots" appositamente costruito (che punta a se stesso o con riferimenti incrociati) causa una ricorsione infinita in "PDFDoc::markAnnotations --> PDFDoc::markPageObjects --> PDFDoc::markObject --> PDFDoc::markDictionary", poiché l'indirizzo del puntatore al dizionario utilizzato per il rilevamento dei cicli cambia a ogni chiamata a fetch(). Un attaccante remoto può causare un denial of service (blocco o crash dell'applicazione) elaborando un file PDF dannoso.

Qui ho costruito un file PDF dannoso (poppler-pdfseparate-poc) in cui "/Annots" viene risolto in un dizionario autoreferenziale o con riferimenti incrociati, facendo sì che la ricorsione markAnnotations --> markPageObjects --> markObject --> markDictionary di Poppler non riesca a rilevare il ciclo, esaurendo così lo stack delle chiamate (ricorsione infinita). Per sfruttare questa vulnerabilità è sufficiente aprire o elaborare un file PDF (ad esempio, utilizzando lo strumento pdfseparate).

I passaggi per la riproduzione sono i seguenti:```bash
afl_env(base) user@ubuntu:~/zgd/AFLProject/pdf_parsers/poppler-25.04.0/build/utils$ ./pdfseparate ./../../../../pdf_fuzz/p
oppler-master/pdfseparate/analyze_crashes/only_custom/all_crashes/poppler-pdfseparate-poc /dev/null
Segmentation fault (core dumped)

afl_env(base) user@ubuntu:~/zgd/AFLProject/pdf_parsers/poppler-25.04.0/build/utils$ gdb ./pdfseparate core.2332378 
GNU gdb (Ubuntu 12.1-0ubuntu1~22.04.2) 12.1
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Reading symbols from ./pdfseparate...
[New LWP 2332378]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
--Type <RET> for more, q to quit, c to continue without paging--
Core was generated by `./pdfseparate ./../../../../pdf_fuzz/poppler-master/pdfseparate/analyze_crashes'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007a27410a3dee in _int_malloc (av=av@entry=0x7a274121ac80 <main_arena>, bytes=bytes@entry=40)
    at ./malloc/malloc.c:3903
3903    ./malloc/malloc.c: No such file or directory.
(gdb) bt
#0  0x00007a27410a3dee in _int_malloc (av=av@entry=0x7a274121ac80 <main_arena>, bytes=bytes@entry=40)
    at ./malloc/malloc.c:3903
#1  0x00007a27410a5262 in __GI___libc_malloc (bytes=40) at ./malloc/malloc.c:3321
#2  0x00007a27414ae98c in operator new(unsigned long) () from /lib/x86_64-linux-gnu/libstdc++.so.6
#3  0x00007a274192a080 in __gnu_cxx::new_allocator<std::_Rb_tree_node<int> >::allocate (this=0x5c29c1b2a498, __n=1)
    at /usr/include/c++/11/ext/new_allocator.h:127
#4  0x00007a2741929c8f in std::allocator<std::_Rb_tree_node<int> >::allocate (__n=1, this=0x5c29c1b2a498)
    at /usr/include/c++/11/bits/allocator.h:185
#5  std::allocator_traits<std::allocator<std::_Rb_tree_node<int> > >::allocate (__a=..., __n=1)
    at /usr/include/c++/11/bits/alloc_traits.h:464
#6  0x00007a274192974f in std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::_M_get_node
    (this=0x5c29c1b2a498) at /usr/include/c++/11/bits/stl_tree.h:561
#7  0x00007a2741973466 in std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::_M_create_node<int const&> (this=0x5c29c1b2a498) at /usr/include/c++/11/bits/stl_tree.h:611
#8  0x00007a2741970c97 in std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::_Alloc_node::operator()<int const&> (this=0x7ffeba55f200, __arg=@0x7ffeba55f2a0: 4) at /usr/include/c++/11/bits/stl_tree.h:529
#9  0x00007a274196ba22 in std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::_M_insert_<int const&, std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::_Alloc_node> (
    this=0x5c29c1b2a498, __x=0x0, __p=0x5c29c1b2a4a0, __v=@0x7ffeba55f2a0: 4, __node_gen=...)
    at /usr/include/c++/11/bits/stl_tree.h:1784
#10 0x00007a2741963f5e in std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::_M_insert_unique<int const&> (this=0x5c29c1b2a498, __v=@0x7ffeba55f2a0: 4) at /usr/include/c++/11/bits/stl_tree.h:2129
#11 0x00007a274195c4f6 in std::set<int, std::less<int>, std::allocator<int> >::insert (this=0x5c29c1b2a498, 
--Type <RET> for more, q to quit, c to continue without paging--
    __x=@0x7ffeba55f2a0: 4) at /usr/include/c++/11/bits/stl_set.h:512
#12 0x00007a2741957c6d in RefRecursionChecker::insert (this=0x5c29c1b2a498, ref=...)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/Object.h:133
#13 0x00007a2741b0e09c in XRef::fetch (this=0x5c29c1b2a370, num=4, gen=0, recursion=0, endPos=0x0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/XRef.cc:1202
#14 0x00007a2741b0dfb4 in XRef::fetch (this=0x5c29c1b2a370, ref=..., recursion=0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/XRef.cc:1190
#15 0x00007a2741a94e1d in Object::fetch (this=0x5c29c208a1c0, xref=0x5c29c1b2a370, recursion=0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/Object.cc:110
#16 0x00007a27419785d3 in Array::get (this=0x5c29c208a160, i=0, recursion=0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/Array.cc:92
#17 0x00007a2741ab0514 in PDFDoc::markAnnotations (this=0x5c29c1b2a0a0, annotsObj=0x7ffeba55f6b0, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldPageNum=3, newPageNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1856
#18 0x00007a2741aaf6b3 in PDFDoc::markDictionary (this=0x5c29c1b2a0a0, dict=0x5c29c208a100, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1716
#19 0x00007a2741aaf8d8 in PDFDoc::markObject (this=0x5c29c1b2a0a0, obj=0x7ffeba55f800, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1744
#20 0x00007a2741ab03af in PDFDoc::markPageObjects (this=0x5c29c1b2a0a0, pageDict=0x5c29c208a0a0, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1840
--Type <RET> for more, q to quit, c to continue without paging--
#21 0x00007a2741ab0827 in PDFDoc::markAnnotations (this=0x5c29c1b2a0a0, annotsObj=0x7ffeba55f9a0, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldPageNum=3, newPageNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1889
#22 0x00007a2741aaf6b3 in PDFDoc::markDictionary (this=0x5c29c1b2a0a0, dict=0x5c29c2089f10, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1716
#23 0x00007a2741aaf8d8 in PDFDoc::markObject (this=0x5c29c1b2a0a0, obj=0x7ffeba55faf0, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1744
#24 0x00007a2741ab03af in PDFDoc::markPageObjects (this=0x5c29c1b2a0a0, pageDict=0x5c29c2089eb0, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1840
#25 0x00007a2741ab0827 in PDFDoc::markAnnotations (this=0x5c29c1b2a0a0, annotsObj=0x7ffeba55fc90, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldPageNum=3, newPageNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1889
#26 0x00007a2741aaf6b3 in PDFDoc::markDictionary (this=0x5c29c1b2a0a0, dict=0x5c29c2089d20, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1716
#27 0x00007a2741aaf8d8 in PDFDoc::markObject (this=0x5c29c1b2a0a0, obj=0x7ffeba55fde0, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1744
#28 0x00007a2741ab03af in PDFDoc::markPageObjects (this=0x5c29c1b2a0a0, pageDict=0x5c29c2089cc0, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
--Type <RET> for more, q to quit, c to continue without paging--
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1840
#29 0x00007a2741ab0827 in PDFDoc::markAnnotations (this=0x5c29c1b2a0a0, annotsObj=0x7ffeba55ff80, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldPageNum=3, newPageNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1889
#30 0x00007a2741aaf6b3 in PDFDoc::markDictionary (this=0x5c29c1b2a0a0, dict=0x5c29c2089b30, xRef=0x5c29c1b2b080, 
    countRef=0x5c29c1b2b240, numOffset=0, oldRefNum=3, newRefNum=259, alreadyMarkedDicts=0x5c29c1b2c9f0)
    at /home/user/zgd/AFLProject/pdf_parsers/poppler-25.04.0/poppler/PDFDoc.cc:1716