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Back to active CVEs
High · CVSS 7.8CVE-2021-47175

net/sched: fq_pie: fix OOB access in the traffic pathCVE-2021-47175

Answer in brief

CVE-2021-47175 records a High severity (CVSS 7.8) vulnerability in net/sched: fq_pie: fix OOB access in the traffic path. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Mar 25, 2024Updated Aug 5, 2026Source checked Nov 3, 2026First seen by HOL Aug 4, 2026Material review Aug 5, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 7.8
Exploitation
Not marked as known exploited
Affected software
6 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Linux/Linuxgeneric>=ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <e6294c06e7c62ffdd5bf3df696d3a4fcbb753d3c || >=ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <7a1bdec12e43e29cc34a4394590337069d8812ce || >=ec97ecf1ebe485a17cd8395a5f35e6b80b57665a <e70f7a11876a1a788ceadf75e9e5f7af2c868680e6294c06e7c62ffdd5bf3df696d3a4fcbb753d3c, 7a1bdec12e43e29cc34a4394590337069d8812ce, e70f7a11876a1a788ceadf75e9e5f7af2c868680
Linux/Linuxgeneric5.6Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
  2. 2Review the reported fix. Update Linux/Linux to e6294c06e7c62ffdd5bf3df696d3a4fcbb753d3c if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Mar 25, 2024

    Evidence: source:cvelist:source_dates:source-dates:record
  2. Source modified

    Aug 5, 2026

    Evidence: source:cvelist:source_dates:source-dates:record
  3. First seen by HOL

    Aug 4, 2026

Sources and claim methodology

  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
Upstream source description

In the Linux kernel, the following vulnerability has been resolved: net/sched: fq_pie: fix OOB access in the traffic path the following script: # tc qdisc add dev eth0 handle 0x1 root fq_pie flows 2 # tc qdisc add dev eth0 clsact # tc filter add dev eth0 egress matchall action skbedit priority 0x10002 # ping 192.0.2.2 -I eth0 -c2 -w1 -q produces the following splat: BUG: KASAN: slab-out-of-bounds in fq_pie_qdisc_enqueue+0x1314/0x19d0 [sch_fq_pie] Read of size 4 at addr ffff888171306924 by task ping/942 CPU: 3 PID: 942 Comm: ping Not tainted 5.12.0+ #441 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 Call Trace: dump_stack+0x92/0xc1 print_address_description.constprop.7+0x1a/0x150 kasan_report.cold.13+0x7f/0x111 fq_pie_qdisc_enqueue+0x1314/0x19d0 [sch_fq_pie] __dev_queue_xmit+0x1034/0x2b10 ip_finish_output2+0xc62/0x2120 __ip_finish_output+0x553/0xea0 ip_output+0x1ca/0x4d0 ip_send_skb+0x37/0xa0 raw_sendmsg+0x1c4b/0x2d00 sock_sendmsg+0xdb/0x110 __sys_sendto+0x1d7/0x2b0 __x64_sys_sendto+0xdd/0x1b0 do_syscall_64+0x3c/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fe69735c3eb Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89 RSP: 002b:00007fff06d7fb38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055e961413700 RCX: 00007fe69735c3eb RDX: 0000000000000040 RSI: 000055e961413700 RDI: 0000000000000003 RBP: 0000000000000040 R08: 000055e961410500 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff06d81260 R13: 00007fff06d7fb40 R14: 00007fff06d7fc30 R15: 000055e96140f0a0 Allocated by task 917: kasan_save_stack+0x19/0x40 __kasan_kmalloc+0x7f/0xa0 __kmalloc_node+0x139/0x280 fq_pie_init+0x555/0x8e8 [sch_fq_pie] qdisc_create+0x407/0x11b0 tc_modify_qdisc+0x3c2/0x17e0 rtnetlink_rcv_msg+0x346/0x8e0 netlink_rcv_skb+0x120/0x380 netlink_unicast+0x439/0x630 netlink_sendmsg+0x719/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5ba/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x3c/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff888171306800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 36 bytes to the right of 256-byte region [ffff888171306800, ffff888171306900) The buggy address belongs to the page: page:00000000bcfb624e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x171306 head:00000000bcfb624e order:1 compound_mapcount:0 flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) raw: 0017ffffc0010200 dead000000000100 dead000000000122 ffff888100042b40 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888171306800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888171306880: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc >ffff888171306900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff888171306980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888171306a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fix fq_pie traffic path to avoid selecting 'q->flows + q->flows_cnt' as a valid flow: it's an address beyond the allocated memory.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Out-of-bounds read vulnerability in CoAP message parsing impacts Qt CoAPAlso CWE-125
  • Libslirp: libslirp: out-of-bounds heap read in icmp_forward_error() leading to information disclosureAlso CWE-125

Record context

Vulnerability class
Buffer Overflow
EPSS
Not reported
CWE IDs
CWE-125
Source
CVE List V5
Source checked
Nov 3, 2026
References
3 linked sources
Open source record