diff --git a/src/Makefile.gtest.include b/src/Makefile.gtest.include
index fa9d47448..2f3100f11 100644
--- a/src/Makefile.gtest.include
+++ b/src/Makefile.gtest.include
@@ -13,7 +13,8 @@ hush_gtest_SOURCES = \
 	gtest/utils.cpp \
 	gtest/test_randomx_preverify.cpp \
 	gtest/test_hdtransparent.cpp \
-	gtest/test_mnemonic_compat.cpp
+	gtest/test_mnemonic_compat.cpp \
+	gtest/test_stratum_jobid.cpp
 
 hush_gtest_CPPFLAGS = $(AM_CPPFLAGS) -DMULTICORE -fopenmp -DBINARY_OUTPUT -DCURVE_ALT_BN128 -DSTATIC $(BITCOIN_INCLUDES)
 hush_gtest_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
diff --git a/src/gtest/test_stratum_jobid.cpp b/src/gtest/test_stratum_jobid.cpp
new file mode 100644
index 000000000..7c248a6a9
--- /dev/null
+++ b/src/gtest/test_stratum_jobid.cpp
@@ -0,0 +1,98 @@
+// Copyright (c) 2016-2026 The Hush developers
+// Distributed under the GPLv3 software license, see the accompanying
+// file COPYING or https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// Regression coverage for the b3e81f1ed fix:
+//   "stratum: do not abort the daemon on a malformed 63-character job_id"
+//
+// The EWBF "31 bytes job_id" path in stratum_mining_submit() completes a
+// 63-character job_id with each hex digit in turn and feeds the result to
+// uint256(). ParseHex() stops at the first non-hex character and returns a
+// SHORT vector without signalling an error, and base_blob's vector ctor
+// asserts vch.size() == 32. asserts are live in release builds here, and the
+// job_id arrives from an unauthenticated client -- so a single mining.submit
+// whose 63-character job_id contains any non-hex byte (63 spaces will do)
+// used to abort the node.
+//
+// The fix size-checks each candidate before constructing uint256. These tests
+// pin the exact invariant that guard relies on, using the real ParseHex and
+// uint256 primitives, without ever constructing a uint256 from a short vector
+// (which would still abort under the guard we are protecting).
+
+#include <gtest/gtest.h>
+#include <string>
+#include <vector>
+
+#include "uint256.h"
+#include "utilstrencodings.h"
+
+namespace {
+
+const std::string HEXDIGITS = "0123456789abcdef";
+
+// Mirrors the guarded completion loop in stratum_mining_submit(): try every
+// single-hex-digit completion and report whether ANY of them parses to a
+// whole 32-byte value. Only then is uint256() construction reached.
+bool AnyCompletionParsesTo32(const std::string& jobid) {
+    for (char d : HEXDIGITS) {
+        std::vector<unsigned char> vch = ParseHex(jobid + d);
+        if (vch.size() == 32) return true;
+    }
+    return false;
+}
+
+} // namespace
+
+// The exact example from the fix commit: a 63-character job_id of spaces.
+// No completion may reach a 32-byte vector, so the daemon never constructs
+// uint256() and never aborts.
+TEST(StratumJobId, AllSpacesNeverYields32Bytes) {
+    std::string spaces(63, ' ');
+    ASSERT_EQ(spaces.size(), 63u);
+    for (char d : HEXDIGITS) {
+        EXPECT_NE(ParseHex(spaces + d).size(), 32u)
+            << "completion '" << d << "' unexpectedly produced 32 bytes";
+    }
+    EXPECT_FALSE(AnyCompletionParsesTo32(spaces));
+}
+
+// A single non-hex byte embedded in an otherwise-hex 63-char job_id is enough:
+// ParseHex stops at it, so every completion is short.
+TEST(StratumJobId, SingleNonHexByteInMiddleIsRejected) {
+    std::string jobid(63, 'a');
+    jobid[30] = 'g'; // 'g' is not a hex digit
+    ASSERT_EQ(jobid.size(), 63u);
+    EXPECT_FALSE(AnyCompletionParsesTo32(jobid));
+}
+
+// A non-hex byte at the very end (position 62) is likewise rejected: the last
+// hex pair can never complete to a whole byte.
+TEST(StratumJobId, NonHexByteAtEndIsRejected) {
+    std::string jobid(62, 'a');
+    jobid.push_back('z'); // length 63, last char non-hex
+    ASSERT_EQ(jobid.size(), 63u);
+    EXPECT_FALSE(AnyCompletionParsesTo32(jobid));
+}
+
+// A genuine truncated EWBF job_id -- 63 real hex characters -- must complete
+// to exactly 32 bytes for every digit, so uint256() construction is safe.
+TEST(StratumJobId, ValidSixtyThreeHexCompletesToExactly32Bytes) {
+    std::string jobid(63, 'a');
+    ASSERT_EQ(jobid.size(), 63u);
+    for (char d : HEXDIGITS) {
+        std::vector<unsigned char> vch = ParseHex(jobid + d);
+        ASSERT_EQ(vch.size(), 32u) << "completion '" << d << "'";
+        // 32-byte vector: construction must not trip the size assertion.
+        uint256 h(vch);
+        EXPECT_EQ(h.size(), 32u);
+    }
+    EXPECT_TRUE(AnyCompletionParsesTo32(jobid));
+}
+
+// Sanity anchors for ParseHex's odd/even handling that the loop depends on:
+// an odd hex length drops the trailing nibble (63 hex -> 31 bytes), and one
+// more hex char fills the 32nd byte (64 hex -> 32 bytes).
+TEST(StratumJobId, ParseHexOddLengthDropsTrailingNibble) {
+    EXPECT_EQ(ParseHex(std::string(63, 'a')).size(), 31u);
+    EXPECT_EQ(ParseHex(std::string(64, 'a')).size(), 32u);
+}