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CVE-2026-53402— fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于fbcon_do_set_font函数的err_out错误路径中缺少对hi_font状态及屏幕缓冲区的回滚逻辑，导致状态机损坏，可能造成越界读取和内核内存泄露。

CVSS 7.1 · High EPSS 0.14% · P3

Affected Version Matrix 22

VendorProduct Version RangeStatus
Linux Linux 868749a7456dc48e93887a8474194e2ee6d6c21f< cb016bcb40c81e7b19c4ae6143babb366dae8e20 affected
ebd6f886aa2447fcfcdce5450c9e1028e1d681bb< ac562193c36696513ae196171892e9338475c4bc affected
a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24< 3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5 affected
a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24< a7a526fbc847f07ad3a503c7382189be5ab68574 affected
a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24< b5bb2c696e140c399cb874def2feedf61dee27d6 affected
a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24< 076b1aa65f77a49bce5a48a4a55a397cfcafa2b8 affected
a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24< 39815715cbcfabb16fc8c5f4a23deeda20f5df62 affected
a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24< 8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2 affected
… +14 more rows
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I. Basic Information for CVE-2026-53402

Vulnerability Information
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Vulnerability Title
fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font() When fbcon_do_set_font() fails (e.g., due to a memory allocation failure inside vc_resize() under heavy memory pressure), it jumps to the `err_out` label to roll back the console state. However, the current rollback logic forgets to restore the `hi_font` state, leading to a severe state machine corruption. Earlier in the function, `set_vc_hi_font()` might be called to change `vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()` subsequently fails, the `err_out` path restores `vc_font.charcount` but entirely skips rolling back the `vc_hi_font_mask` and the screen buffer. This mismatch leaves the terminal in a desynchronized state. Because `vc_hi_font_mask` remains set, the VT subsystem will still accept character indices greater than 255 from userspace and write them to the screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will then use these inflated indices to access the reverted, 256-character font array, leading to a deterministic out-of-bounds read and potential kernel memory disclosure. Fix this by adding the missing rollback logic for the `hi_font` mask and screen buffer in the error path.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于fbcon_do_set_font函数的err_out错误路径中缺少对hi_font状态及屏幕缓冲区的回滚逻辑，导致状态机损坏，可能造成越界读取和内核内存泄露。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 868749a7456dc48e93887a8474194e2ee6d6c21f ~ cb016bcb40c81e7b19c4ae6143babb366dae8e20 -
Linux Linux 6.0 -

II. Public POCs for CVE-2026-53402

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III. Intelligence Information for CVE-2026-53402

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Patches & Fixes for CVE-2026-53402 (8)

Same Patch Batch · Linux · 2026-07-19 · 429 CVEs total

CVE-2026-63795 10.0 CRITICAL 9p: avoid putting oldfid in p9_client_walk() error path
CVE-2026-64033 9.8 CRITICAL RDMA/rtrs: Fix use-after-free in path file creation cleanup
CVE-2026-53399 9.8 CRITICAL nfsd: release layout stid on setlease failure
CVE-2026-53398 9.8 CRITICAL NFSD: Fix SECINFO_NO_NAME decode error cleanup
CVE-2026-64037 9.8 CRITICAL wifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled
CVE-2026-63984 9.8 CRITICAL ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress()
CVE-2026-63979 9.8 CRITICAL net/handshake: hand off the pinned file reference to accept_doit
CVE-2026-63800 9.8 CRITICAL pNFS: Fix use-after-free in pnfs_update_layout()
CVE-2026-63978 9.8 CRITICAL net/handshake: Drain pending requests at net namespace exit
CVE-2026-64056 9.8 CRITICAL net: ethernet: cortina: Make RX SKB per-port
CVE-2026-63808 9.8 CRITICAL exfat: fix potential use-after-free in exfat_find_dir_entry()
CVE-2026-64055 9.8 CRITICAL net: ethernet: cortina: Carry over frag counter
CVE-2026-64142 9.8 CRITICAL ksmbd: close durable scavenger races against m_fp_list lookups
CVE-2026-64089 9.8 CRITICAL batman-adv: tt: fix negative last_changeset_len
CVE-2026-63922 9.8 CRITICAL ipv6: exthdrs: refresh nh after handling HAO option
CVE-2026-64091 9.8 CRITICAL batman-adv: tt: fix TOCTOU race for reported vlans
CVE-2026-64160 9.8 CRITICAL netfs: Fix potential for tearing in ->remote_i_size and ->zero_point
CVE-2026-64035 9.8 CRITICAL igc: set tx buffer type for SMD frames
CVE-2026-63888 9.8 CRITICAL scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd()
CVE-2026-64162 9.8 CRITICAL idpf: fix read_dev_clk_lock spinlock init in idpf_ptp_init()

Showing top 20 of 429 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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