diff --git a/math/OpenBLAS/Portfile b/math/OpenBLAS/Portfile
index 013bb854476..d2837d84744 100644
--- a/math/OpenBLAS/Portfile
+++ b/math/OpenBLAS/Portfile
@@ -23,14 +23,16 @@ subport OpenBLAS-devel {}
 
 if {[string first "-devel" $subport] > 0} {
 
-    github.setup    OpenMathLib OpenBLAS 9b3cc7835bd98439924cd6b9d1bf5e951b950bc0
+    github.setup    OpenMathLib OpenBLAS 1bd74ad3d1e8d21f86d1a6be35abfcdf27c0208a
     github.tarball_from archive
-    version         20260402-[string range ${github.version} 0 7]
-    checksums       rmd160  bd861aab88b42eece021ac94846228bb3681ee7c \
-                    sha256  dbd477ad6cc88f650f99d7820dd6202eed322df6afb96072f32ed4c313146b7c \
-                    size    25282237
+    version         20260525-[string range ${github.version} 0 7]
+    checksums       rmd160  1b051d45ce4bdd52cda9b4b2953432684ad4c575 \
+                    sha256  8fdc9a8fdc5577555d9cb04b5e984e1cc6761a3cf52a6ca02ffb00364a972c1b \
+                    size    25289812
     revision        0
 
+    patchfiles
+
     conflicts       OpenBLAS
 
     github.livecheck.branch develop
@@ -45,7 +47,7 @@ if {[string first "-devel" $subport] > 0} {
     checksums       rmd160  150ffad95ea1b37e9c53515660d61bd2671c49a4 \
                     sha256  6761af1d9f5d353ab4f0b7497be2643313b36c8f31caec0144bfef198e71e6ab \
                     size    25256012
-    revision        0
+    revision        1
 
     conflicts       OpenBLAS-devel
 
@@ -75,6 +77,9 @@ variant native description "Force compilation on machine to get fully optimized
 xcode_workaround.fixed_xcode_version 11.2
 xcode_workaround.type append_to_compiler_name
 
+# backport of upstream fix; see https://trac.macports.org/ticket/74022
+patchfiles-append   5820.diff
+
 if {${muniversal.build_arch} in [list arm64 ppc64 x86_64]} {
     configure.args-append \
                     -DBINARY64=ON
diff --git a/math/OpenBLAS/files/5820.diff b/math/OpenBLAS/files/5820.diff
new file mode 100644
index 00000000000..f12cdb7be42
--- /dev/null
+++ b/math/OpenBLAS/files/5820.diff
@@ -0,0 +1,16 @@
+Upstream fix: https://github.com/OpenMathLib/OpenBLAS/pull/5820
+for issue: https://github.com/OpenMathLib/OpenBLAS/issues/5818
+diff --git a/lapack/getf2/zgetf2_k.c b/lapack/getf2/zgetf2_k.c
+index 6a2137b3e7..e2c2f75f65 100644
+--- lapack/getf2/zgetf2_k.c.orig
++++ lapack/getf2/zgetf2_k.c
+@@ -51,7 +51,8 @@ blasint CNAME(blas_arg_t *args, BLASLONG *range_m, BLASLONG *range_n, FLOAT *sa,
+   blasint *ipiv;
+   FLOAT *a;
+ 
+-  FLOAT temp1, temp2, temp3, temp4, ratio, den;
++  volatile FLOAT temp1;
++  FLOAT temp2, temp3, temp4, ratio, den;
+   blasint i, j;
+   blasint ip, jp;
+   blasint info;