CVE-2026-23266

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-03-18. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

fbdev: rivafb: fix divide error in nv3_arb()

A userspace program can trigger the RIVA NV3 arbitration code by calling the FBIOPUT_VSCREENINFO ioctl on /dev/fb*. When doing so, the driver recomputes FIFO arbitration parameters in nv3_arb(), using state->mclk_khz (derived from the PRAMDAC MCLK PLL) as a divisor without validating it first.

In a normal setup, state->mclk_khz is provided by the real hardware and is non-zero. However, an attacker can construct a malicious or misconfigured device (e.g. a crafted/emulated PCI device) that exposes a bogus PLL configuration, causing state->mclk_khz to become zero. Once nv3_get_param() calls nv3_arb(), the division by state->mclk_khz in the gns calculation causes a divide error and crashes the kernel.

Fix this by checking whether state->mclk_khz is zero and bailing out before doing the division.

The following log reveals it:

rivafb: setting virtual Y resolution to 2184 divide error: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 PID: 2187 Comm: syz-executor.0 Not tainted 5.18.0-rc1+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 RIP: 0010:nv3_arb drivers/video/fbdev/riva/riva_hw.c:439 [inline] RIP: 0010:nv3_get_param+0x3ab/0x13b0 drivers/video/fbdev/riva/riva_hw.c:546 Call Trace: nv3CalcArbitration.constprop.0+0x255/0x460 drivers/video/fbdev/riva/riva_hw.c:603 nv3UpdateArbitrationSettings drivers/video/fbdev/riva/riva_hw.c:637 [inline] CalcStateExt+0x447/0x1b90 drivers/video/fbdev/riva/riva_hw.c:1246 riva_load_video_mode+0x8a9/0xea0 drivers/video/fbdev/riva/fbdev.c:779 rivafb_set_par+0xc0/0x5f0 drivers/video/fbdev/riva/fbdev.c:1196 fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1033 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1188 __x64_sys_ioctl+0x122/0x190 fs/ioctl.c:856

CVSS v3
5.5
EG Score
5.5(medium)
EPSS
1.8%
KEV
Not listed

Published

March 18, 2026

Last Modified

May 29, 2026

References (8)

Vendor Advisories for CVE-2026-23266(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.10.251—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
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  1. 2026-06-29 14:06 UTCEPSS rescore
  2. 2026-06-29 06:02 UTCOSV refresh
  3. 2026-06-28 14:07 UTCEPSS rescore
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  26. 2026-06-12 23:12 UTCEPSS rescore
  27. 2026-06-11 23:48 UTCEG score recompute
  28. 2026-06-11 23:48 UTCVendor advisory
  29. 2026-06-11 23:48 UTCGHSA enrichment
  30. 2026-06-11 14:00 UTCEPSS rescore
  31. 2026-06-10 22:18 UTCEPSS rescore
  32. 2026-06-10 18:00 UTCEG score recompute
  33. 2026-06-10 18:00 UTCVendor advisory
  34. 2026-06-10 18:00 UTCGHSA enrichment
  35. 2026-06-10 13:22 UTCEPSS rescore
  36. 2026-06-09 16:33 UTCEG score recompute
  37. 2026-06-09 16:33 UTCVendor advisory
  38. 2026-06-09 16:33 UTCGHSA enrichment
  39. 2026-06-08 14:17 UTCEPSS rescore
  40. 2026-06-08 14:17 UTCEPSS rescore
  41. 2026-06-07 15:25 UTCEPSS rescore
  42. 2026-06-07 15:24 UTCEPSS rescore
  43. 2026-06-07 14:25 UTCEG score recompute
  44. 2026-06-07 14:25 UTCVendor advisory
  45. 2026-06-07 14:25 UTCGHSA enrichment
  46. 2026-06-05 22:47 UTCEPSS rescore
  47. 2026-06-05 06:10 UTCEPSS rescore
  48. 2026-06-05 06:10 UTCEPSS rescore
  49. 2026-06-04 13:12 UTCEPSS rescore
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  62. 2026-05-29 20:23 UTCEG score recompute
  63. 2026-05-29 20:23 UTCVendor advisory
  64. 2026-05-29 20:23 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-23266?
CVE-2026-23266 is a medium vulnerability published on March 18, 2026. In the Linux kernel, the following vulnerability has been resolved: fbdev: rivafb: fix divide error in nv3_arb() A userspace program can trigger the RIVA NV3 arbitration code by calling the FBIOPUT_VSCREENINFO ioctl on /dev/fb*. When doing so, the driver recomputes FIFO arbitration parameters in…
When was CVE-2026-23266 disclosed?
CVE-2026-23266 was first published in the National Vulnerability Database on March 18, 2026, with the most recent update on May 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23266 actively exploited?
CVE-2026-23266 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-23266?
CVE-2026-23266 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-23266?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23266, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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