# CVE-2024-26798: linux: In the Linux kernel, the following vulnerability has been resolved: fbcon: always restore the old font data in fbcon... CVE-2024-26798 is fixed in 22 products on 1 platform, first by DEBIAN-CVE-2024-26798, released April 4, 2024. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2024-26798 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0033 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 4, 2024 ## Description In the Linux kernel, the following vulnerability has been resolved: fbcon: always restore the old font data in fbcon_do_set_font() Commit a5a923038d70 (fbdev: fbcon: Properly revert changes when vc_resize() failed) started restoring old font data upon failure (of vc_resize()). But it performs so only for user fonts. It means that the "system"/internal fonts are not restored at all. So in result, the very first call to fbcon_do_set_font() performs no restore at all upon failing vc_resize(). This can be reproduced by Syzkaller to crash the system on the next invocation of font_get(). It's rather hard to hit the allocation failure in vc_resize() on the first font_set(), but not impossible. Esp. if fault injection is used to aid the execution/failure. It was demonstrated by Sirius: BUG: unable to handle page fault for address: fffffffffffffff8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD cb7b067 P4D cb7b067 PUD cb7d067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8007 Comm: poc Not tainted 6.7.0-g9d1694dc91ce #20 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:fbcon_get_font+0x229/0x800 drivers/video/fbdev/core/fbcon.c:2286 Call Trace: con_font_get drivers/tty/vt/vt.c:4558 [inline] con_font_op+0x1fc/0xf20 drivers/tty/vt/vt.c:4673 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline] vt_ioctl+0x632/0x2ec0 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0x6f8/0x1570 drivers/tty/tty_io.c:2803 vfs_ioctl fs/ioctl.c:51 [inline] ... So restore the font data in any case, not only for user fonts. Note the later 'if' is now protected by 'old_userfont' and not 'old_data' as the latter is always set now. (And it is supposed to be non-NULL. Otherwise we would see the bug above again.) ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | bpftool-debuginfo amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-debuginfo amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-devel amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-headers amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-libbpf amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-libbpf-devel amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-libbpf-static amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-livepatch-6.1.82-99.168 amzn 2023 | 1.0-0.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-modules-extra amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-modules-extra-common amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-tools amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-tools-debuginfo amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | kernel-tools-devel amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | linux Debian 12.15 (bookworm) | 6.1.82-1 | [DEBIAN-CVE-2024-26798](https://patchblox.com/security/data/fix/linux/debian-cve-2024-26798.md) | Apr 4, 2024 | | Linux | linux Debian 13.5 (trixie) | 6.7.9-1 | [DEBIAN-CVE-2024-26798](https://patchblox.com/security/data/fix/linux/debian-cve-2024-26798.md) | Apr 4, 2024 | | Linux | linux Debian 14 | 6.7.9-1 | [DEBIAN-CVE-2024-26798](https://patchblox.com/security/data/fix/linux/debian-cve-2024-26798.md) | Apr 4, 2024 | | Linux | perf amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | perf-debuginfo amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | python3-perf amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | | Linux | python3-perf-debuginfo amzn 2023 | 6.1.82-99.168.amzn2023 | [ALAS2023-2024-784](https://patchblox.com/security/data/fix/linux/alas2023-2024-784.md) | Dec 5, 2024 | --- Data as of 2026-11-08T19:12:23Z UTC. 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