5.5

CVE-2026-23266: linux Divide By Zero

CVSS: 5.5v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-23266DEBIAN-CVE-2026-23266
Published 18-03-2026Last modified 11-05-2026
Open JSON

Vulnerability summary

CVE-2026-23266 is a medium (CVSS 5.5) Divide By Zero vulnerability in linux. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.6% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.12%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 29 · Related 27
MGASA-2026-0097MGASA-2026-0098SUSE-SU-2026:21834-1SUSE-SU-2026:2238-1USN-8492-1USN-8492-2

Timeline

  1. 18-03-2026
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

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 metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.12%

Chance of exploitation in the next 30 days

Percentile

2%

Versus all other CVEs

30-day change

+0.01 pp

From 0.11% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.12%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu157 products
  • linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-134.134
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1060.63
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ec5a58f4fd581875593ea92a65485e1906a53c0f | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 52916878db2b8e3769743a94484729f0844352df | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 526460a96c5443e2fc0fd231edd1f9c49d2de26b | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 78daf5984d96edec3b920c72a93bd6821b8710b7 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 9efa0dc46270a8723c158c64afbcf1dead72b28c | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 73f0391e92d404da68f7484e57c106c5e673dc7e | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 0209e21e3c372fa2da04c39214bec0b64e4eb5f4 | 2.6.12
  • linux_kernel≥ 2.6.12.1, < 5.10.251 | ≥ 5.11, < 5.15.201 | ≥ 5.16, < 6.1.164 | ≥ 6.2, < 6.6.127 | ≥ 6.7, < 6.12.74 | ≥ 6.13, < 6.18.13 | ≥ 6.19, < 6.19.3 | 2.6.12 | 2.6.12:rc2 | 2.6.12:rc3 | 2.6.12:rc4 | 2.6.12:rc5
Debian1 product
  • linux< 6.1.164-1 | < 6.12.74-1 | < 6.18.13-1

3 vendors · 160 products

References

38 links
Show all 38 references