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CVE Record

CVE-2024-39480: kdb: Fix buffer overflow during tab-complete

In the Linux kernel, the following vulnerability has been resolved: kdb: Fix buffer overflow during tab-complete Currently, when the user attempts symbol completion with the Tab key, kdb will use strncpy() to insert the completed symbol into the command buffer. Unfortunately it passes the size of the source buffer rather than the destination to strncpy() with predictably horrible results. Most obviously if the command buffer is already full but cp, the cursor position, is in the middle of the buffer, then we will write past the end of the supplied buffer. Fix this by replacing the dubious strncpy() calls with memmove()/memcpy() calls plus explicit boundary checks to make sure we have enough space before we start moving characters around.

HighCVSS 8.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in Linux kernel debugger (kdb) tab completion can overwrite memory when completing a symbol into a nearly full command buffer. Triggering requires interaction with kdb, concentrating exposure on systems where that debugger is available and accessible. Memory corruption can cause serious compromise or crashes, but the bundle provides no evidence of active exploitation.

Executive priority

Prioritize prompt assessment where kdb is enabled or accessible, especially on sensitive or multi-user systems. Patch those systems through supported kernel channels. Systems without accessible kdb appear less exposed, but teams should verify configuration and backport status rather than assuming safety from version numbers alone.

Technical view

kdb passed the source-buffer length to strncpy() while writing into the command buffer. If the buffer was full and the cursor was in its middle, completion could exceed the destination. Fixes use memmove()/memcpy() with capacity checks. This is CWE-121 with CVSS 3.1 score 8.4: local, low-complexity, no privileges or user interaction, and high C/I/A impact.

Likely exposure

Affected Linux kernel lines may be exposed when a user can invoke kdb and use symbol tab completion. Normal network reachability is not identified as an attack path. Actual exposure depends on the running kernel, inclusion of the relevant stable fix, and kdb accessibility. Distribution backports are not documented in the bundle.

Exploitation context

The bundle reports KEV status as false and cites no observed exploitation or public exploit. The CVSS vector describes a local, low-complexity condition requiring no privileges or separate user interaction, but practical access to kdb remains an important environmental constraint. Exploit reliability and real-world outcomes are not established by the supplied evidence.

Researcher notes

The root cause is an incorrect destination bound during in-place kdb command completion. The affected data mixes release identifiers and commit hashes, so branch-specific fixes should be mapped through vendor metadata. Sources establish an out-of-bounds write and corrective boundary checks, but do not establish reliable code execution, exploitation in the wild, or distribution-specific package versions.

Mitigation direction

  • Inventory running kernel versions and compare them with the affected ranges and branch-specific stable fixes.
  • Update affected systems to a vendor-supported kernel containing the applicable upstream fix.
  • Until updated, restrict access to interfaces allowing users to enter kdb.
  • Review distribution guidance for patched package versions and any additional mitigations.

Validation and detection

  • Confirm the installed kernel package includes the stable fix for its maintained branch.
  • Verify whether kdb is built, enabled, and reachable by untrusted or low-privileged users.
  • After updating, confirm the new kernel is running, not merely installed.
  • Review kernel logs for unusual kdb activity; absence of events does not disprove exploitation.
Prepared
Confidence
medium
Sources
10

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

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cwe · low confidence lookup

CWE-121: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2024-39480 mapping review

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

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

2CVSS vectors
3Timeline events
2ADP providers
9Source links

SSVC decision data

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

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.4CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H2.55.9Linux
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

8.4High
CVSS 3.1 vector shape for CVE-2024-39480Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux5d5314d6795f3c1c0f415348ff8c51f7de042b77, 5d5314d6795f3c1c0f415348ff8c51f7de042b77, 5d5314d6795f3c1c0f415348ff8c51f7de042b77, 5d5314d6795f3c1c0f415348ff8c51f7de042b77, 5d5314d6795f3c1c0f415348ff8c51f7de042b77, 5d5314d6795f3c1c0f415348ff8c51f7de042b77, 5d5314d6795f3c1c0f415348ff8c51f7de042b77, 5d5314d6795f3c1c0f415348ff8c51f7de042b77unaffected
LinuxLinux2.6.35, 0, 4.19.316, 5.4.278, 5.10.219, 5.15.161, 6.1.94, 6.6.34, 6.9.5, 6.10affected
Weakness

CWE details

CWE-121

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

CWE-121 · source CWE mapping

Stack-based Buffer Overflow

Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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