by Kastro
Paper/Archive/CVE-2026-5450

CVE-2026-5450

The GNU C Library glibc — scanf %mc off-by-one heap buffer overflow

EPSS 0.5%public exploitCVSS 9.8
critical.is priorityof 100
48
CVSS 9.8 (ADP)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 42.9.429 × 208.6Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

Calling the scanf family of functions with a %mc (malloc'd character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow.

Affected

ProductAffectedFixed inSource
glibc2.7–CNA
SIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 – < V3.1.6V3.1.6siemens-SADP
SIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 – < V3.1.6V3.1.6siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.5 – < V3.1.6V3.1.6siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.5 – < V3.1.6V3.1.6siemens-SADP
SIPLUS S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 – < V3.1.6V3.1.6siemens-SADP

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitsourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450refinbox.sourceware.org/libc-announce/[email protected]/T/#urefcert-portal.siemens.com/productcert/html/ssa-082556.html