CVE-2026-64550 (GCVE-0-2026-64550)
Vulnerability from cvelistv5
Published
2026-07-27 20:10
Modified
2026-08-17 04:57
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: qualcomm: rmnet: validate MAP frame length before ingress parsing
When ingress deaggregation is disabled, rmnet_map_ingress_handler() passes
the skb straight to __rmnet_map_ingress_handler(), skipping the length
validation that rmnet_map_deaggregate() performs on the aggregated path.
The parser then dereferences the MAP header and csum header/trailer based on
the on-wire pkt_len without checking skb->len, so a short frame is read out
of bounds:
BUG: KASAN: slab-out-of-bounds in rmnet_map_checksum_downlink_packet
Read of size 1 at addr ffff88801118ed00 by task exploit/147
Call Trace:
...
rmnet_map_checksum_downlink_packet (drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:413)
__rmnet_map_ingress_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:96)
rmnet_rx_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:129)
__netif_receive_skb_core.constprop.0 (net/core/dev.c:6089)
netif_receive_skb (net/core/dev.c:6460)
tun_get_user (drivers/net/tun.c:1955)
tun_chr_write_iter (drivers/net/tun.c:2001)
vfs_write (fs/read_write.c:688)
ksys_write (fs/read_write.c:740)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
...
Factor that validation out of rmnet_map_deaggregate() into
rmnet_map_validate_packet_len() and run it on the no-aggregation path too.
The MAP header is bounds-checked first, since this path can receive a frame
shorter than the header.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: ceed73a2cf4aff2921802aa3d21d45280677547d Version: ceed73a2cf4aff2921802aa3d21d45280677547d Version: ceed73a2cf4aff2921802aa3d21d45280677547d Version: ceed73a2cf4aff2921802aa3d21d45280677547d Version: ceed73a2cf4aff2921802aa3d21d45280677547d Version: ceed73a2cf4aff2921802aa3d21d45280677547d Version: ceed73a2cf4aff2921802aa3d21d45280677547d Version: ceed73a2cf4aff2921802aa3d21d45280677547d |
||
{
"containers": {
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"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c",
"drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h",
"drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h",
"drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "4.14"
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"version": "0",
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"status": "unaffected",
"version": "5.10.261",
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{
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"status": "unaffected",
"version": "5.15.212",
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},
{
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"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
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"version": "6.12.97",
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},
{
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"status": "unaffected",
"version": "7.1.5",
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},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
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],
"negate": false,
"operator": "OR"
}
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: qualcomm: rmnet: validate MAP frame length before ingress parsing\n\nWhen ingress deaggregation is disabled, rmnet_map_ingress_handler() passes\nthe skb straight to __rmnet_map_ingress_handler(), skipping the length\nvalidation that rmnet_map_deaggregate() performs on the aggregated path.\nThe parser then dereferences the MAP header and csum header/trailer based on\nthe on-wire pkt_len without checking skb-\u003elen, so a short frame is read out\nof bounds:\n\n BUG: KASAN: slab-out-of-bounds in rmnet_map_checksum_downlink_packet\n Read of size 1 at addr ffff88801118ed00 by task exploit/147\n Call Trace:\n ...\n rmnet_map_checksum_downlink_packet (drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:413)\n __rmnet_map_ingress_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:96)\n rmnet_rx_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:129)\n __netif_receive_skb_core.constprop.0 (net/core/dev.c:6089)\n netif_receive_skb (net/core/dev.c:6460)\n tun_get_user (drivers/net/tun.c:1955)\n tun_chr_write_iter (drivers/net/tun.c:2001)\n vfs_write (fs/read_write.c:688)\n ksys_write (fs/read_write.c:740)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n ...\n\nFactor that validation out of rmnet_map_deaggregate() into\nrmnet_map_validate_packet_len() and run it on the no-aggregation path too.\nThe MAP header is bounds-checked first, since this path can receive a frame\nshorter than the header."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.3,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The vulnerability is reached by `write()` to a tun fd owned by the attacker, exactly as in the reporter\u0027s KASAN trace (`tun_chr_write_iter` \u2192 `netif_receive_skb` \u2192 `rmnet_rx_handler`), requiring a local account. Although rmnet can be stacked on an Ethernet device (commit 74692caf1b0b), the universally available and demonstrated vector is local.\nAC:L - Every precondition is attacker-chosen \u2014 the `data_format` flags (deaggregation off, CKSUMV4 on) via `IFLA_RMNET_FLAGS`, the frame length, and the `pkt_len`/`pad` fields that select the OOB offset \u2014 with no race, timing, or uncontrolled memory-layout dependency. The trigger is a single deterministic `write()` that can be repeated indefinitely to sweep offsets.\nPR:L - Only an unprivileged local account is needed: `/dev/net/tun` is world-accessible, and both `TUNSETIFF` and `rtnl_newlink` gate on namespace-scoped `ns_capable`/`netlink_net_capable(CAP_NET_ADMIN)`, which `unshare -Urn` grants without real root.\nUI:N - The attacker creates the tun device, the rmnet link, and writes the malformed frame entirely on its own. No victim action or pre-existing configuration is required.\nS:U - The out-of-bounds access and its consequences are confined to kernel memory within the same security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is an attacker-positioned read up to 65535 bytes past a small slab object, and the result is disclosed back to userspace through the unprivileged rmnet ethtool counters \u2014 because the pseudo-header checksum is computed from the attacker\u0027s own IP header, the exact 16-bit heap word at a chosen offset is recoverable in a few probes, yielding a precise heap-read primitive for KASLR bypass and secret disclosure.\nI:L - There is no arbitrary write, but out-of-bounds data determines `skb-\u003eip_summed = CHECKSUM_UNNECESSARY`, causing packets whose checksums were never validated to be accepted by the IP stack as verified. On the MAP-command path `rmnet_map_send_ack()` also writes `cmd-\u003ecmd_type` past the end of a short frame after `skb_trim()` underflows into a no-op.\nA:H - A 64 KB overshoot from a small kmalloc object can land on an unmapped page (guard pages, DEBUG_PAGEALLOC/hardened allocators, memory-region edges), faulting in kernel context and producing an oops; on the real WWAN receive path (ipa/qmi_wwan/mhi_net NAPI) this executes in softirq, where the fault is a panic. KASAN builds abort immediately, as the reporter\u0027s trace shows."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:57:27.672Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/ed25befc8c36f896b5878f9078faddb67fd7e2d0"
},
{
"url": "https://git.kernel.org/stable/c/a54d76d176e50d2fdbd39b7231efe256170339e4"
},
{
"url": "https://git.kernel.org/stable/c/00f4c366dbca16a40772c3b7ec2d8cba839e9724"
},
{
"url": "https://git.kernel.org/stable/c/3868c3244369ab709a90c9aad7534d406009b824"
},
{
"url": "https://git.kernel.org/stable/c/14eb0c9491385d5361a292ea4974aec0e6887299"
},
{
"url": "https://git.kernel.org/stable/c/1b12612c367e4be9b0814c0468e7e687835315b4"
},
{
"url": "https://git.kernel.org/stable/c/231a8a4b76cb1b1827b3b19d7b3603642f5aaaef"
},
{
"url": "https://git.kernel.org/stable/c/f0f1887a9e30712a1df03e152dce6fb91344b1f3"
}
],
"title": "net: qualcomm: rmnet: validate MAP frame length before ingress parsing",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64550",
"datePublished": "2026-07-27T20:10:39.459Z",
"dateReserved": "2026-07-19T15:36:31.796Z",
"dateUpdated": "2026-08-17T04:57:27.672Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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