{ "dataType": "CVE_RECORD", "cveMetadata": { "cveId": "CVE-2024-26994", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-19T14:20:24.206Z", "datePublished": "2024-05-01T05:28:07.350Z", "dateUpdated": "2026-08-05T11:28:53.774Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:28:53.774Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nspeakup: Avoid crash on very long word\n\nIn case a console is set up really large and contains a really long word\n(> 256 characters), we have to stop before the length of the word buffer." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The overflow is reached only through the speakup console screen-reader command path (`keyboard_notifier_call` → `speakup_key` → `do_spkup` → `get_word`) combined with `VT_RESIZE`/`PIO_UNIMAP`/`KDFONTOP` ioctls on the attacker's own virtual console, all of which require a local session on the machine. There is no network or remote protocol handler involved, but console/VT access is standard local access rather than physical device attachment.\nAC:L - Every precondition is under the attacker's control: `vt_ioctl()` grants `perm=1` to the tty owner, so an unprivileged console user can `VT_RESIZE` the console past 257 columns (up to `VC_MAXCOL`=32767 outright when the VC is bound to dummycon, which has no `con_resize` clamp, or via a narrow `KDFONTOP` font under fbcon), then print a >256-character word and press the say-word key. No race, no memory-layout luck, and on 4K framebuffer consoles the stock 8x16 font already yields 480 columns by default.\nPR:L - The attacker needs an ordinary unprivileged local account owning a virtual console — `current->signal->tty == tty` alone satisfies the VT ioctl permission check, so no CAP_SYS_TTY_CONFIG or root is required, and `do_spkup()` performs no capability check before invoking `get_word()`.\nUI:N - The attacker performs every step themselves — resizing their own VT, loading the unimap, painting the long word, and issuing the speakup say-word/spell-word command; no separate victim needs to be induced into any action.\nS:U - The out-of-bounds write corrupts kernel `.bss` belonging to the same kernel security authority that contains the vulnerable code; no VM, hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - The linear overflow lands on `spk_characters[256]`, a pointer array immediately following `buf` in `.bss`, whose entries are dereferenced and printed via `synth_printf(\"%s\", cp)` into the synth buffer that userspace reads from `/dev/softsynth` — giving an arbitrary kernel-memory read primitive disclosed to the attacker, well beyond a bounded leak.\nI:H - This is an out-of-bounds write of fully attacker-chosen 16-bit values (sourced from an attacker-loaded `inverse_trans_unicode` table) with attacker-chosen length, overwriting adjacent `.bss` pointer arrays such as `spk_our_keys[]` and `speakup_console[]`, the latter being dereferenced for writes (`speakup_console[vc_num]->ht.highbuf[bi][hi] = ic[i]`) — an arbitrary-write and control-flow-influence primitive.\nA:H - Even without careful exploitation, smashing kilobytes of `.bss` past `buf[256]` corrupts live pointer arrays that speakup dereferences on the next key event, producing an immediate kernel oops/panic — the crash the commit title explicitly refers to." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/accessibility/speakup/main.c" ], "versions": [ { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "756c5cb7c09e537b87b5d3acafcb101b2ccf394f", "status": "affected", "versionType": "git" }, { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "8f6b62125befe1675446923e4171eac2c012959c", "status": "affected", "versionType": "git" }, { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "6401038acfa24cba9c28cce410b7505efadd0222", "status": "affected", "versionType": "git" }, { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "0d130158db29f5e0b3893154908cf618896450a8", "status": "affected", "versionType": "git" }, { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "89af25bd4b4bf6a71295f07e07a8ae7dc03c6595", "status": "affected", "versionType": "git" }, { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "8defb1d22ba0395b81feb963b96e252b097ba76f", "status": "affected", "versionType": "git" }, { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "0efb15c14c493263cb3a5f65f5ddfd4603d19a76", "status": "affected", "versionType": "git" }, { "version": "c6e3fd22cd538365bfeb82997d5b89562e077d42", "lessThan": "c8d2f34ea96ea3bce6ba2535f867f0d4ee3b22e1", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/accessibility/speakup/main.c" ], "versions": [ { "version": "2.6.37", "status": "affected" }, { "version": "0", "lessThan": "2.6.37", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.313", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.275", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.216", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.157", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.88", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.29", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8.8", "lessThanOrEqual": "6.8.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.9", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "4.19.313" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "5.4.275" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "5.10.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "5.15.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.1.88" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.6.29" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.8.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/756c5cb7c09e537b87b5d3acafcb101b2ccf394f" }, { "url": "https://git.kernel.org/stable/c/8f6b62125befe1675446923e4171eac2c012959c" }, { "url": "https://git.kernel.org/stable/c/6401038acfa24cba9c28cce410b7505efadd0222" }, { "url": "https://git.kernel.org/stable/c/0d130158db29f5e0b3893154908cf618896450a8" }, { "url": "https://git.kernel.org/stable/c/89af25bd4b4bf6a71295f07e07a8ae7dc03c6595" }, { "url": "https://git.kernel.org/stable/c/8defb1d22ba0395b81feb963b96e252b097ba76f" }, { "url": "https://git.kernel.org/stable/c/0efb15c14c493263cb3a5f65f5ddfd4603d19a76" }, { "url": "https://git.kernel.org/stable/c/c8d2f34ea96ea3bce6ba2535f867f0d4ee3b22e1" } ], "title": "speakup: Avoid crash on very long word", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "problemTypes": [ { "descriptions": [ { "type": "CWE", "lang": "en", "description": "CWE-noinfo Not enough information" } ] } ], "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", 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