CVE-2020-36791
CVE-2020-36791 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: High (CVSS 3.x base score 7.1)
- EPSS exploit prediction: 0% (5th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2020-24232
- Weakness: CWE-125
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
In the Linux kernel, the following vulnerability has been resolved: net_sched: keep alloc_hash updated after hash allocation In commit 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex") I moved cp->hash calculation before the first tcindex_alloc_perfect_hash(), but cp->alloc_hash is left untouched. This difference could lead to another out of bound access. cp->alloc_hash should always be the size allocated, we should update it after this tcindex_alloc_perfect_hash().
Frequently asked questions
- What is CVE-2020-36791?
- In the Linux kernel, the following vulnerability has been resolved: net_sched: keep alloc_hash updated after hash allocation In commit 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex") I moved cp->hash calculation before the first tcindex_alloc_perfect_hash(), but cp->alloc_hash is left untouched. This difference could lead to another out of bound access. cp->alloc_hash should always be the size allocated, we should update it after this tcindex_alloc_perfect_hash().
- How severe is CVE-2020-36791?
- CVE-2020-36791 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
- Is CVE-2020-36791 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-36791?
- CVE-2020-36791 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2020-36791?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2020-36791 have an EU (EUVD) identifier?
- Yes. CVE-2020-36791 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2020-24232.
- When was CVE-2020-36791 published?
- CVE-2020-36791 was published on 2025-05-07 and last updated on 2026-06-17.
References
- https://blog.cdthoughts.ch/2021/03/16/syzbot-bug.html
- https://git.kernel.org/stable/c/0d1c3530e1bd38382edef72591b78e877e0edcd3
- https://git.kernel.org/stable/c/557d015ffb27b672e24e6ad141fd887783871dc2
- https://git.kernel.org/stable/c/9f8b6c44be178c2498a00b270872a6e30e7c8266
- https://git.kernel.org/stable/c/bd3ee8fb6371b45c71c9345cc359b94da2ddefa9
- https://git.kernel.org/stable/c/c4453d2833671e3a9f6bd52f0f581056c3736386
- https://git.kernel.org/stable/c/d23faf32e577922b6da20bf3740625c1105381bf
- https://git.kernel.org/stable/c/d6cdc5bb19b595486fb2e6661e5138d73a57f454
- https://syzkaller.appspot.com/bug?id=ea260693da894e7b078d18fca2c9c0a19b457534
Affected products (8)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.6:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.6:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.6:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.6:rc4:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.6:rc5:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.6:rc6:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.6:rc7:*:*:*:*:*:*
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