CVE-2025-21689USB: serial: quatech2: fix null-ptr-deref in qt2_process_read_urb()
- 5.5MediumCVSS base score
- 0.23%Exploitation in 30 daysEPSS · top 86% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: USB: serial: quatech2: fix null-ptr-deref in qt2_process_read_urb() This patch addresses a null-ptr-deref in qt2_process_read_urb() due to an incorrect bounds check in the following: if (newport > serial->num_ports) { dev_err(&port->dev, "%s - port change to invalid port: %i\n", __func__, newport); break; } The condition doesn't account for the valid range of the serial->port buffer, which is from 0 to serial->num_ports - 1. When newport is equal to serial->num_ports, the assignment of "port" in the following code is out-of-bounds and NULL: serial_priv->current_port = newport; port = serial->port[serial_priv->current_port]; The fix checks if newport is greater than or equal to serial->num_ports indicating it is out-of-bounds.
Timeline
ID reserved
By Linux
- 43 days later
· 43 days later
Published
- 15 months later
· 15 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.23% · top 86% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < fa4c7472469d97c4707698b4c0e098f8cfc2bf22
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < 94770cf7c5124f0268d481886829dc2beecc4507
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < 6068dcff7f19e9fa6fa23ee03453ad6a40fa4efe
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < 4b9b41fabcd38990f69ef0cee9c631d954a2b530
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < 6377838560c03b36e1153a42ef727533def9b68f
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < f371471708c7d997f763b0e70565026eb67cc470
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < 8542b33622571f54dfc2a267fce378b6e3840b8b
- affected f7a33e608d9ae022b7f49307921627e34e9484ed – < 575a5adf48b06a2980c9eeffedf699ed5534fade
- affected 3.5
- unaffected < 3.5
- unaffected 5.4.290 – ≤ 5.4.*
- unaffected 5.10.234 – ≤ 5.10.*
- unaffected 5.15.178 – ≤ 5.15.*
- unaffected 6.1.128 – ≤ 6.1.*
- unaffected 6.6.75 – ≤ 6.6.*
- unaffected 6.12.12 – ≤ 6.12.*
- unaffected 6.13.1 – ≤ 6.13.*
- unaffected 6.14 – ≤ *
References
References10
- https://git.kernel.org/stable/c/fa4c7472469d97c4707698b4c0e098f8cfc2bf22 (opens in a new tab)
- https://git.kernel.org/stable/c/94770cf7c5124f0268d481886829dc2beecc4507 (opens in a new tab)
- https://git.kernel.org/stable/c/6068dcff7f19e9fa6fa23ee03453ad6a40fa4efe (opens in a new tab)
- https://git.kernel.org/stable/c/4b9b41fabcd38990f69ef0cee9c631d954a2b530 (opens in a new tab)
- https://git.kernel.org/stable/c/6377838560c03b36e1153a42ef727533def9b68f (opens in a new tab)
- https://git.kernel.org/stable/c/f371471708c7d997f763b0e70565026eb67cc470 (opens in a new tab)
- https://git.kernel.org/stable/c/8542b33622571f54dfc2a267fce378b6e3840b8b (opens in a new tab)
- https://git.kernel.org/stable/c/575a5adf48b06a2980c9eeffedf699ed5534fade (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-2638 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-21689)Record last updated .