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CVE Record

CVE-2022-49948: vt: Clear selection before changing the font

In the Linux kernel, the following vulnerability has been resolved: vt: Clear selection before changing the font When changing the console font with ioctl(KDFONTOP) the new font size can be bigger than the previous font. A previous selection may thus now be outside of the new screen size and thus trigger out-of-bounds accesses to graphics memory if the selection is removed in vc_do_resize(). Prevent such out-of-memory accesses by dropping the selection before the various con_font_set() console handlers are called.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue affects virtual terminal font changes. If a console selection exists and the font change changes screen sizing, the kernel could access graphics memory outside the expected bounds. The public record does not provide a CVSS score or confirmed exploitation.

Executive priority

Treat as a kernel maintenance priority, not an internet-facing emergency based on current evidence. Patch through normal kernel update channels, with higher urgency for shared Linux systems or environments with local console access.

Technical view

The flaw is in Linux vt handling around ioctl(KDFONTOP). A larger replacement font can make an existing selection fall outside the resized screen, causing out-of-bounds graphics-memory access when vc_do_resize() removes that selection. The stable fix clears the selection before con_font_set() handlers run.

Likely exposure

Exposure is likely limited to Linux systems using the virtual terminal console path where console font changes are possible. The source bundle lists affected Linux kernel versions and stable commits, but does not define affected distributions or required privileges.

Exploitation context

The provided sources do not report active exploitation, and the CVE is not marked KEV. The described trigger involves changing a console font while an old selection exists; no remote attack path is identified in the source bundle.

Researcher notes

The key behavior is selection lifetime across font-driven console resizing. Validate by code/version review against the referenced stable commits. Do not assume distro impact from upstream hashes alone; confirm backports in vendor packages.

Mitigation direction

  • Update to a kernel containing the referenced stable fixes.
  • Check your Linux distribution advisory for backported kernel packages.
  • Prioritize systems allowing interactive local console use.
  • If patching is delayed, follow vendor guidance; no workaround is named here.

Validation and detection

  • Inventory kernel versions against the CVE affected version data.
  • Confirm distro kernel changelogs include the vt selection-clearing fix.
  • Review whether virtual terminal console functionality is enabled and used.
  • Verify patched hosts boot the updated kernel, not only install it.
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

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CVE-2022-49948 mapping review

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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
0ADP providers
9Source links

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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux009e39ae44f4191188aeb6dfbf661b771dbbe515, 009e39ae44f4191188aeb6dfbf661b771dbbe515, 009e39ae44f4191188aeb6dfbf661b771dbbe515, 009e39ae44f4191188aeb6dfbf661b771dbbe515, 009e39ae44f4191188aeb6dfbf661b771dbbe515, 009e39ae44f4191188aeb6dfbf661b771dbbe515, 009e39ae44f4191188aeb6dfbf661b771dbbe515, 009e39ae44f4191188aeb6dfbf661b771dbbe515, e60f8fcce05042e8f8cea25ee81fecc1222114cf, 5812a9bc9d68a82c2cc839f88e6f7a05093ab39d, 863ad19fd654c485e3beec3575c4d74a1e74369e, dbc3fd44f957a39407e889287bf61fa0ef3ecc14, 0b2a0a58ad22f9d6dfc641bc5ec46057493f22a5, 9f2d48f0745f921040df91bfe8fa7f0339cd7497, 3425e397fb23cc2e8e6fb8f5b8226dcb447e84dd, eeae0a12a16650ff494d5faefa371cd9e7079575unaffected
LinuxLinux4.9, 0, 4.9.328, 4.14.293, 4.19.258, 5.4.213, 5.10.142, 5.15.66, 5.19.8, 6.0affected
Weakness

CWE details

No CWE listed

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