Bug 2484207 (CVE-2026-27145) - CVE-2026-27145 crypto/x509: golang: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries
Summary: CVE-2026-27145 crypto/x509: golang: golang crypto/x509: Denial of Service via...
Keywords:
Status: NEW
Alias: CVE-2026-27145
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2494205 2494206 2494207 2494208 2494209 2494210 2494211 2494212 2494213 2494214 2494215 2494216 2494217 2494218 2494219 2494220 2494221 2494222 2494223 2494224 2494225 2494226 2494227 2494228 2494229 2494230 2494231 2494232 2494233 2494234 2494235 2494236 2494238 2494239 2494240 2494241 2494242 2494243 2494244 2494245 2494247 2494248 2494250 2494251 2494252 2494253 2494254 2494255 2494256 2494257 2494258 2494259 2494260 2494261 2494262 2494263 2494264 2494265 2494266 2494267 2494269 2494270 2494271 2494273 2494275 2494276 2494277 2494278 2494279 2494280 2494281 2494284 2494285 2494287 2494289 2494290 2494291 2494292 2494293 2494294 2494295 2494296 2494297 2494298 2494300 2494301 2494302 2494304 2494306 2494307 2494308 2494309 2494310 2494311 2494312 2494313 2494314 2494315 2494317 2494318 2494319 2494320 2494321 2494322 2494323 2494324 2494325 2494327 2494329 2494330 2494331 2494332 2494333 2494334 2494335 2494336 2494337 2494338 2494339 2494340 2494341 2494342 2494343 2494344 2494346 2494347 2494348 2494349 2494350 2494354 2494355 2494356 2494357 2494358 2494360 2494361 2494362 2494363 2494364 2494365 2494366 2494367 2494368 2494369 2494370 2494371 2494372 2494373 2494374 2494376 2494377 2494378 2494379 2494380 2494381 2494382 2494383 2494384 2494385 2494386 2494387 2494388 2494389 2494390 2494392 2494393 2494394 2494395 2494396 2494397 2494398 2494399 2494403 2494404 2494405 2494406 2494407 2494408 2494409 2494418 2494246 2494249 2494272 2494282 2494283 2494299 2494316 2494326 2494345 2494359 2494375 2494391 2494400 2494401 2494402
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-02 23:01 UTC by OSIDB Bzimport
Modified: 2026-07-14 01:23 UTC (History)
155 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:34357 0 None None None 2026-07-01 18:36:31 UTC
Red Hat Product Errata RHSA-2026:34359 0 None None None 2026-07-01 19:21:25 UTC
Red Hat Product Errata RHSA-2026:35832 0 None None None 2026-07-06 03:06:09 UTC
Red Hat Product Errata RHSA-2026:36317 0 None None None 2026-07-07 17:57:05 UTC
Red Hat Product Errata RHSA-2026:38995 0 None None None 2026-07-13 14:12:42 UTC
Red Hat Product Errata RHSA-2026:39005 0 None None None 2026-07-13 16:00:21 UTC

Description OSIDB Bzimport 2026-06-02 23:01:31 UTC 
(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates.
Comment 11 errata-xmlrpc 2026-07-01 18:36:23 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:34357 https://access.redhat.com/errata/RHSA-2026:34357
Comment 12 errata-xmlrpc 2026-07-01 19:21:18 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:34359 https://access.redhat.com/errata/RHSA-2026:34359
Comment 13 errata-xmlrpc 2026-07-06 03:05:59 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:35832 https://access.redhat.com/errata/RHSA-2026:35832
Comment 16 errata-xmlrpc 2026-07-07 17:56:57 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:36317 https://access.redhat.com/errata/RHSA-2026:36317
Comment 20 errata-xmlrpc 2026-07-13 14:12:34 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:38995 https://access.redhat.com/errata/RHSA-2026:38995
Comment 21 errata-xmlrpc 2026-07-13 16:00:11 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:39005 https://access.redhat.com/errata/RHSA-2026:39005
Comment 22 Fedora Update System 2026-07-14 01:23:32 UTC 
FEDORA-2026-d7dfd8e9ba (golang-github-openprinting-ipp-usb-0.9.34-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.
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