5.5

CVE-2024-26998: serial: core: Clearing the circular buffer before NULLifying it

Modified
AliasesUBUNTU-CVE-2024-26998DEBIAN-CVE-2024-26998
Published 01-05-2024Last modified 23-05-2026

Vulnerability summary

CVE-2024-26998 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.23%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 4
MGASA-2024-0263MGASA-2024-0266USN-6893-1USN-6893-2USN-6893-3USN-6918-1

Timeline

  1. 01-05-2024
    PublishedVulnerability first disclosed.
  2. 23-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: serial: core: Clearing the circular buffer before NULLifying it The circular buffer is NULLified in uart_tty_port_shutdown() under the spin lock. However, the PM or other timer based callbacks may still trigger after this event without knowning that buffer pointer is not valid. Since the serial code is a bit inconsistent in checking the buffer state (some rely on the head-tail positions, some on the buffer pointer), it's better to have both aligned, i.e. buffer pointer to be NULL and head-tail possitions to be the same, meaning it's empty. This will prevent asynchronous calls to dereference NULL pointer as reported recently in 8250 case: BUG: kernel NULL pointer dereference, address: 00000cf5 Workqueue: pm pm_runtime_work EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) ... ? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) __start_tx (drivers/tty/serial/8250/8250_port.c:1551) serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654) serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63) __rpm_callback (drivers/base/power/runtime.c:393) ? serial_port_remove (drivers/tty/serial/serial_port.c:50) rpm_suspend (drivers/base/power/runtime.c:447) The proposed change will prevent ->start_tx() to be called during suspend on shut down port.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.23% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu78 products
  • linux< 6.8.0-38.38
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 6.8.0-1011.12
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 434beb66368d4fb4d3119c2116b9398500adbf47, < 7ae7104d54342433a3a73975f6569beefdd86350 | ≥ 43066e32227ecde674e8ae1fcdd4a1ede67680c2, < bb1118905e875c111d7ccef9aee86ac5e4e7f985 | ≥ 43066e32227ecde674e8ae1fcdd4a1ede67680c2, < 9cf7ea2eeb745213dc2a04103e426b960e807940 | a629a9b2f7699314a4abe8fbc37b0ee667b60f33 | ≥ 6.6.24, < 6.6.29 | ≥ 6.7.12, < 6.8 | 6.8
  • linux_kernel≥ 6.6.24, < 6.6.29 | ≥ 6.7.12, < 6.8 | ≥ 6.8, < 6.8.8 | 6.9:rc1 | 6.9:rc2 | 6.9:rc3 | 6.9:rc4
Debian1 product
  • linux< 6.8.9-1

3 vendors · 81 products

References

14 links
Show all 14 references