LiveActive security incident?Get immediate response
CVE Record

CVE-2020-36776: thermal/drivers/cpufreq_cooling: Fix slab OOB issue

In the Linux kernel, the following vulnerability has been resolved: thermal/drivers/cpufreq_cooling: Fix slab OOB issue Slab OOB issue is scanned by KASAN in cpu_power_to_freq(). If power is limited below the power of OPP0 in EM table, it will cause slab out-of-bound issue with negative array index. Return the lowest frequency if limited power cannot found a suitable OPP in EM table to fix this issue. Backtrace: [<ffffffd02d2a37f0>] die+0x104/0x5ac [<ffffffd02d2a5630>] bug_handler+0x64/0xd0 [<ffffffd02d288ce4>] brk_handler+0x160/0x258 [<ffffffd02d281e5c>] do_debug_exception+0x248/0x3f0 [<ffffffd02d284488>] el1_dbg+0x14/0xbc [<ffffffd02d75d1d4>] __kasan_report+0x1dc/0x1e0 [<ffffffd02d75c2e0>] kasan_report+0x10/0x20 [<ffffffd02d75def8>] __asan_report_load8_noabort+0x18/0x28 [<ffffffd02e6fce5c>] cpufreq_power2state+0x180/0x43c [<ffffffd02e6ead80>] power_actor_set_power+0x114/0x1d4 [<ffffffd02e6fac24>] allocate_power+0xaec/0xde0 [<ffffffd02e6f9f80>] power_allocator_throttle+0x3ec/0x5a4 [<ffffffd02e6ea888>] handle_thermal_trip+0x160/0x294 [<ffffffd02e6edd08>] thermal_zone_device_check+0xe4/0x154 [<ffffffd02d351cb4>] process_one_work+0x5e4/0xe28 [<ffffffd02d352f44>] worker_thread+0xa4c/0xfac [<ffffffd02d360124>] kthread+0x33c/0x358 [<ffffffd02d289940>] ret_from_fork+0xc/0x18

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel bug can make thermal CPU power management read outside a kernel memory array under specific power-limit conditions. The public record does not state real-world exploitation, business impact, or CVSS severity. Treat it as a kernel stability and potential memory-safety issue where affected Linux kernels are deployed.

Executive priority

Handle through normal kernel patch governance unless affected systems are safety-critical, embedded, or difficult to reboot. Escalate if vulnerable kernels manage production workloads where thermal instability or kernel crashes could cause outage risk.

Technical view

The flaw is in thermal/drivers/cpufreq_cooling cpu_power_to_freq(). If limited power is below OPP0 in the Energy Model table, a negative array index can trigger a slab out-of-bounds read detected by KASAN. The fix returns the lowest frequency when no suitable OPP is found.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions with the cpufreq cooling thermal path and Energy Model OPP handling. The bundle lists Linux as affected and includes fixed stable versions and commits, but does not identify distributions, appliances, or cloud images.

Exploitation context

The source bundle marks CISA KEV as false and provides no evidence of active exploitation or public weaponization. The record includes a KASAN crash backtrace, indicating a discovered kernel memory-safety condition rather than a documented attack path.

Researcher notes

Evidence is incomplete: no CVSS, CWE, exploitability statement, or distribution mapping is provided. The key exposure condition is limited power below OPP0 in the Energy Model table, causing negative indexing in cpufreq cooling logic.

Mitigation direction

  • Upgrade to a vendor kernel that includes the referenced stable fixes.
  • Prioritize systems using affected Linux kernel branches and thermal CPU frequency cooling.
  • Check distribution advisories for backported fixes before relying on version numbers alone.
  • If patching is delayed, follow vendor guidance for supported mitigations.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and embedded devices.
  • Confirm whether kernel packages include the cpufreq_cooling slab OOB fix.
  • Compare deployed kernels against listed affected and fixed versions or commits.
  • Review kernel logs for thermal, cpufreq, KASAN, or slab out-of-bounds errors.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2020-36776 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux371a3bc79c11b707d7a1b7a2c938dc3cc042fffb, 371a3bc79c11b707d7a1b7a2c938dc3cc042fffb, 371a3bc79c11b707d7a1b7a2c938dc3cc042fffb, 371a3bc79c11b707d7a1b7a2c938dc3cc042fffb, 39e0651cac9c80865b2838f297f95ffc0f34a1d8, febe56f21371ba1e51e8586c3ddf8f54fc62fe61, d3b7bacd1115400b94482dfc7efffc175c29b831, 9006b543384ab10902819364c1205f11a1458571, 4.14.189, 4.19.134, 5.4.53, 5.7.8unaffected
LinuxLinux5.8, 0, 5.10.36, 5.11.20, 5.12.3, 5.13affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.