CVE-2021-47557
published 2024-05-24CVE-2021-47557: In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR classes…
PriorityP420medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.24%
15.3th percentile
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_ets: don't peek at classes beyond 'nbands'
when the number of DRR classes decreases, the round-robin active list can
contain elements that have already been freed in ets_qdisc_change(). As a
consequence, it's possible to see a NULL dereference crash, caused by the
attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL:
BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 910 Comm: mausezahn Not tainted 5.16.0-rc1+ #475
Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
RIP: 0010:ets_qdisc_dequeue+0x129/0x2c0 [sch_ets]
Code: c5 01 41 39 ad e4 02 00 00 0f 87 18 ff ff ff 49 8b 85 c0 02 00 00 49 39 c4 0f 84 ba 00 00 00 49 8b ad c0 02 00 00 48 8b 7d 10 8b 47 18 48 8b 40 38 0f ae e8 ff d0 48 89 c3 48 85 c0 0f 84 9d
RSP: 0000:ffffbb36c0b5fdd8 EFLAGS: 00010287
RAX: ffff956678efed30 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff9b938dc9 RDI: 0000000000000000
RBP: ffff956678efed30 R08: e2f3207fe360129c R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff956678efeac0
R13: ffff956678efe800 R14: ffff956611545000 R15: ffff95667ac8f100
FS: 00007f2aa9120740(0000) GS:ffff95667b800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000018 CR3: 000000011070c000 CR4: 0000000000350ee0
Call Trace:
qdisc_peek_dequeued+0x29/0x70 [sch_ets]
tbf_dequeue+0x22/0x260 [sch_tbf]
__qdisc_run+0x7f/0x630
net_tx_action+0x290/0x4c0
__do_softirq+0xee/0x4f8
irq_exit_rcu+0xf4/0x130
sysvec_apic_timer_interrupt+0x52/0xc0
asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0033:0x7f2aa7fc9ad4
Code: b9 ff ff 48 8b 54 24 18 48 83 c4 08 48 89 ee 48 89 df 5b 5d e9 ed fc ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 83 ec
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 5.15.15-1 (bookworm) | linux 5.15.15-1 (bookworm) |
| linux | linux | — | — |
| linux | linux | >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 < ae2659d2c670252759ee9c823c4e039c0e05a6f2 | ae2659d2c670252759ee9c823c4e039c0e05a6f2 |
| linux | linux | >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 < e25bdbc7e951ae5728fee1f4c09485df113d013c | e25bdbc7e951ae5728fee1f4c09485df113d013c |
| linux | linux | >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 < de6d25924c2a8c2988c6a385990cafbe742061bf | de6d25924c2a8c2988c6a385990cafbe742061bf |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 5.10.84-1 | 5.10.84-1 |
| linux | linux_kernel | >= 0 < 5.15.15-1 | 5.15.15-1 |
| linux | linux_kernel | >= 0 < 5.15.15-1 | 5.15.15-1 |
| linux | linux_kernel | >= 0 < 5.15.15-1 | 5.15.15-1 |
| linux | linux_kernel | >= 5.11 < 5.15.6 | 5.15.6 |
| linux | linux_kernel | >= 5.6 < 5.10.83 | 5.10.83 |
CVSS provenance
nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
Stop checking back — get the weekly exploitation signal.
Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.
OSV
CVE-2021-47557: In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR c
osv·2024-05-24·CVSS 5.5
CVE-2021-47557 [MEDIUM] CVE-2021-47557: In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR c
In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR classes decreases, the round-robin active list can contain elements that have already been freed in ets_qdisc_change(). As a consequence, it's possible to see a NULL dereference crash, caused by the attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 910 Comm: mausezahn Not tainted 5.16.0-rc1+ #475 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:ets_qdisc_dequeue+0x129/0x2c0 [
Red Hat
kernel: net/sched: sch_ets: don't peek at classes beyond 'nbands'
vendor_redhat·2024-05-24·CVSS 5.5
CVE-2021-47557 [MEDIUM] CWE-476 kernel: net/sched: sch_ets: don't peek at classes beyond 'nbands'
kernel: net/sched: sch_ets: don't peek at classes beyond 'nbands'
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_ets: don't peek at classes beyond 'nbands'
when the number of DRR classes decreases, the round-robin active list can
contain elements that have already been freed in ets_qdisc_change(). As a
consequence, it's possible to see a NULL dereference crash, caused by the
attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL:
BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 910 Comm: mausezahn Not tainted 5.16.0-rc1+ #475
Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0
Debian
CVE-2021-47557: linux - In the Linux kernel, the following vulnerability has been resolved: net/sched: ...
vendor_debian·2021·CVSS 5.5
CVE-2021-47557 [MEDIUM] CVE-2021-47557: linux - In the Linux kernel, the following vulnerability has been resolved: net/sched: ...
In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR classes decreases, the round-robin active list can contain elements that have already been freed in ets_qdisc_change(). As a consequence, it's possible to see a NULL dereference crash, caused by the attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 910 Comm: mausezahn Not tainted 5.16.0-rc1+ #475 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:ets_qdisc_dequeue+0x129/0x2c0 [
No detection rules found.
No public exploits indexed.
https://git.kernel.org/stable/c/ae2659d2c670252759ee9c823c4e039c0e05a6f2https://git.kernel.org/stable/c/de6d25924c2a8c2988c6a385990cafbe742061bfhttps://git.kernel.org/stable/c/e25bdbc7e951ae5728fee1f4c09485df113d013chttps://git.kernel.org/stable/c/ae2659d2c670252759ee9c823c4e039c0e05a6f2https://git.kernel.org/stable/c/de6d25924c2a8c2988c6a385990cafbe742061bfhttps://git.kernel.org/stable/c/e25bdbc7e951ae5728fee1f4c09485df113d013c
2024-05-24
Published