CVE-2026-7259

In PHP versions 8.2.* before 8.2.31, 8.3.* before 8.3.31, 8.4.* before 8.4.21, and 8.5.* before 8.5.6, a mismatch between encoding lists in Oniguruma and mbfl leads to  a NULL pointer dereference, resulting in a segmentation fault and denial of service. The vulnerability is exploitable when user-controlled input can influence the encoding passed to mb_regex_encoding().

Credits

Viet Hoang Luu (The University of Melbourne)
Amirmohammad Pasdar (The University of Melbourne)
Wachiraphan Charoenwet (The University of Melbourne)
Shaanan Cohney (The University of Melbourne)
Toby Murray (The University of Melbourne)
Van-Thuan Pham (The University of Melbourne)
Ilija Tovilo

References