Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-89541— SUNRPC: harden gss_unwrap_resp_priv length checks

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基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于gss_unwrap_resp_priv对RPCSEC_GSS opaque长度检查不当，offset与opaque_len相加在u32运算中发生整数溢出且缺少下界检查，可能导致越界读取。

CVSS 9.8 · Critical EPSS 0.52% · P43

Possible ATT&CK Techniques 1 AI

T1029 · Scheduled Transfer

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< 3691c4b3488d8ca046b9941e5be30c626dbbbb50 affected
2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< 85fa6b12e8f439739ac36ef2aad925f37c8b976a affected
2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< 401f6a5b338d05bb1069ad814d9f77e3c367854f affected
2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< 81fd7654a8429718adfcb2a7e03496077f547ed0 affected
2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< 89a15a50f84d32d4b99db86f957427fcbe20a99a affected
2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< ebcbd2523a8524c3d24e111cdbed8e271d910269 affected
2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< d395c30d570ca6168f0297b191709927d1258273 affected
2d2da60c63b67174add32f06e8d54c3a0c5cd9cf< 87831b92112c81db251d46756d65daa4f91af6a2 affected
… +10 more rows
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-89541

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
SUNRPC: harden gss_unwrap_resp_priv length checks
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: SUNRPC: harden gss_unwrap_resp_priv length checks gss_unwrap_resp_priv() validates the RPCSEC_GSS opaque length with offset = (u8 *)(p) - (u8 *)head->iov_base; if (offset + opaque_len > rcv_buf->len) goto unwrap_failed; maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, offset + opaque_len, rcv_buf); Both operands are u32 and the sum is computed in u32. A reply with opaque_len near 0xffffffff makes offset + opaque_len wrap to a small value that is below rcv_buf->len, so the bound check passes and gss_unwrap() is called with end < begin. The check also lacks a lower bound, so any opaque_len in [0, GSS_KRB5_TOK_HDR_LEN) is accepted and forwarded to gss_krb5_unwrap_v2(), whose pre-decrypt header reads at ptr+4 and ptr+6 then run past the token. A krb5p NFS server returning a crafted RPCSEC_GSS reply can drive the client into out-of-bounds reads in gss_krb5_unwrap_v2() and the rotate_left() loop that follows. Fix by replacing the single combined check with three guards that are safe in u32 arithmetic and that enforce the RFC 4121 minimum outer token length: if (offset > rcv_buf->len) goto unwrap_failed; if (opaque_len > rcv_buf->len - offset) goto unwrap_failed; if (opaque_len < GSS_KRB5_TOK_HDR_LEN) goto unwrap_failed; The first guard makes the subtraction in the second guard unconditionally safe; offset is derived from a successful xdr_inline_decode() in the head kvec, so in practice it already satisfies the bound. The floor mirrors the server-side check added in commit 5b757c2e57a5 ("SUNRPC: svcauth_gss: enforce krb5 token minimum length").
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于gss_unwrap_resp_priv对RPCSEC_GSS opaque长度检查不当，offset与opaque_len相加在u32运算中发生整数溢出且缺少下界检查，可能导致越界读取。
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 2d2da60c63b67174add32f06e8d54c3a0c5cd9cf ~ 3691c4b3488d8ca046b9941e5be30c626dbbbb50 -
Linux Linux 2.6.15 -

II. Public POCs for CVE-2026-89541

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-89541

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-89541 (8)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89688 9.8 CRITICAL nfsd: drop the stateid, not the stateowner, on seqid_op replay retry
CVE-2026-89655 9.8 CRITICAL ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock
CVE-2026-89658 9.8 CRITICAL NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup
CVE-2026-89660 9.8 CRITICAL NFSD: Prevent client use-after-free during admin state revocation
CVE-2026-89659 9.8 CRITICAL NFSD: Prevent client use-after-free during delegation revoke
CVE-2026-89662 9.8 CRITICAL NFSD: Prevent lock owner use-after-free during client teardown
CVE-2026-89669 9.8 CRITICAL nfsd: initialize copy-notify stateid before publishing it
CVE-2026-89674 9.8 CRITICAL nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
CVE-2026-89675 9.8 CRITICAL nfsd: fix UAF in async copy cancel and shutdown
CVE-2026-89676 9.8 CRITICAL nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
CVE-2026-89677 9.8 CRITICAL nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
CVE-2026-89681 9.8 CRITICAL nfsd: fix layout fence worker double-reference race
CVE-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke
CVE-2026-89703 9.8 CRITICAL nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations
CVE-2026-89479 9.8 CRITICAL sctp: stop processing a packet once its association is deleted
CVE-2026-89478 9.8 CRITICAL sctp: drop a chunk if its transport was removed
CVE-2026-89702 9.8 CRITICAL nfsd: size fh_verify server sockaddr slot by xpt_locallen
CVE-2026-89482 9.8 CRITICAL nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89708 9.8 CRITICAL nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown
CVE-2026-89712 9.8 CRITICAL NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-89541

No comments yet

Leave a comment