CVE-2021-33909
HIGH
7.8
CVSS Score
Published: July 20, 2021 at 06:01 PM UTC
Updated: June 17, 2026 at 03:55 AM UTC
8 products affected across 6 vendorsLinux KernelDebian LinuxFedora
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Severity
HIGH7.8
Exploit prediction
EPSS 10%
Description
fs/seq_file.c in the Linux kernel 3.16 through 5.13.x before 5.13.4 does not properly restrict seq buffer allocations, leading to an integer overflow, an Out-of-bounds Write, and escalation to root by an unprivileged user, aka CID-8cae8cd89f05.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Debian Linux· Debiandrupal
95%95%
3.12.43 ≤ v < 3.133.16 ≤ v < 4.4.2764.10 ≤ v < 4.14.2404.15 ≤ v < 4.19.1984.20 ≤ v < 5.4.1344.5 ≤ v < 4.9.2765.11 ≤ v < 5.12.195.13 ≤ v < 5.13.45.5 ≤ v < 5.10.52
Affected range stops below 3.13, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.14.240, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.19.198, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.4.276, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.9.276, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.10.52, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.12.19, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.13.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.4.134, so it looks safe — our inference, not a vendor statement
All versions
Sma1000· SonicWalldevice
80%All versions
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4
- https://github.com/torvalds/linux/commit/8cae8cd89f05f6de223d63e6d15e31c8ba9cf53b
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z4UHHIGISO3FVRF4CQNJS4IKA25ATSFU/
- https://www.debian.org/security/2021/dsa-4941
- https://www.oracle.com/security-alerts/cpujan2022.html
References (20)
x_refsource_MISCExploitThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/163621/Sequoia-A-Deep-Root-In-Linuxs-Filesystem-Layer.htmlx_refsource_MISCThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/163671/Kernel-Live-Patch-Security-Notice-LSN-0079-1.htmlx_refsource_MISCThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.htmlx_refsource_MISCThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.htmlMailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
http://www.openwall.com/lists/oss-security/2021/07/22/7Mailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
http://www.openwall.com/lists/oss-security/2021/08/25/10Mailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
http://www.openwall.com/lists/oss-security/2021/09/17/2Mailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
http://www.openwall.com/lists/oss-security/2021/09/17/4CVSS
- Attack Vector
- LOCAL
- Complexity
- LOW
- Privileges
- LOW
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality
- HIGH
- Integrity
- HIGH
- Availability
- HIGH
Vector?
Quick Info
StatusMODIFIED
CWE
CWE-190CWE-787
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